BMW M4 vs BMW Z4

What's the difference?

We cannot think of a faster or more invigorating four-seater luxury convertible for the money than the new M4 Competition.

Finally, after years of devastatingly fast droptops with remote steering and an unforgiving ride, the G83 generation discovers refinement and sophistication to go with its supersonic speed.

There’s terrific talent on tap here that no rival can even come close to right now. BMW is on a roll and this is the first M4 convertible that can sit proudly alongside the best of its classic M3 ancestors.

The Z4 didn’t make me feel like Peirce Brosnan’s 007. It’s way too serious – a proper gritty reboot. Maybe it’s meant for Daniel Craig. Either way, its brave design makes it one of the best-looking BMWs of recent memory, and it’s a tech- and comfort-fest that the Bavarian automaker should be proud of. I just wish it was a smidge more fun behind the wheel.

Hallelujah! The unloved folding hardtop is history and fabric is back in fashion in a BMW 3/4 Series-based convertible for the first time since the demise of the E46 convertible in 2006.

It improves the proportions and aesthetics out of sight while remaining superbly insulated. It’s also 40 per cent lighter to boot while liberating 80 litres of extra luggage space.

The roof requires just 18 seconds to drop away or erect again, and can be done so at speeds of up to 50km/h. And it looks great, with a taut fit that suits the BMW’s lithe lines to a tee. With all four windows dropped, it also does a fab impression of an American-style pillarless hardtop.

Roof up or down, the M4’s muscular styling has a tense sparseness to it that means business, reinforced by that oversized, M-specific kidney grille treatment that, admittedly, isn’t as divisive in real life. The smiley LED light wave out back also brings a friendlier tone, harmonising handsomely with the rest of the car.

This is probably the best-looking BMW convertible since the beautiful E46 era.

The Z4 is a sight to behold. It’s brave, especially for a BMW, it even betrays the brand’s strongest styling pillars, making its own way with its more horizontal grille design, flat body and curved out rear.

It’s more than that, though. In black, this car looks sinister, brooding. The more you look at it, the more you notice tiny details - the scooped-out sides, or the way the entire rear seems to flick up into the integrated spoiler. I couldn’t get enough of staring at it – it manages to look even better with the roof down.

That’s probably when it hit me. To my eyes, at least, this is the most stunning BMW in years. Sure, the X7 is a sight to behold due to its sheer dimensions and borderline offensive grille, but the Z4 is the opposite. It’s subtle, it hides its details away in its silhouette.

It’s designer, Calvin Luk (an Australian no less), was inspired at least in part by the Z8 – another Brosnan bond car – and you can see the Fisker design reflected in the Z4’s low, flat grille and almost bulbous rear.

Inside, sadly, the Z4’s strong design doesn’t quite play out. There’s no wily Fisker touches here, just a standard set of BMW switchgear. While it all works well, it just dumbs down the Z4’s character.

The big, chunky steering wheel in particular is a let-down. It’s the same wheel that sits in the brand’s X5 SUV, and it feels right there, but not here in a convertible where you’re so close to the ground. A smaller wheel would not only suit this car better, it would make it feel just a smidge more alive. I miss the three-spoke M sport wheel from previous-generation BMW cars.

I do like the dash, which is seemly carved from rhomboid shapes - a theme that rolls into the doors, screens, and vents elegantly. I’m normally not a fan of gloss plastics and chrome touches, but in the Z4 they’re all tastefully applied.

The seats, too, are lovely. I’m not sure about the contrast bright-red leather our car came with, but they’re nice and close to the ground and have excellent trim that you seem to sink into just enough to be comfortable and sporty all at once.

It’s a slick place to be, I just wish it felt less like you were at the helm of an SUV and more like you were driving something that looks this damn good.

The M4 Convertible is not a paragon of space efficiency, given its footprint.

At nearly 4.8 metres long and 1.9m wide, the M4 Convertible casts a sizeable shadow on the road, which only really pays dividends for front-seat occupants inside.

Ours was fitted with a very handsome pair of $7500, two-tone M Carbon bucket seats up front, a sort of futuristic tombstone design with a fixed headrest that looks like they were created by and for Stormtroopers; they do provide all the electronic adjustability one would need in terms of fore/aft, up/down and lumbar support movement.

But, unless you really need their g-force-bracing support and love their outrageous appearance, they are monumentally obstructive to effortless entry/egress and overall hip comfort if you don’t possess a gymnast’s physique. In fact, at times, they can feel downright torturous, especially in the gusset area due to the pointless (ironically) hard central bulge bit. The standard front seat set-up is perfectly fine, offering all the comfort and support expected in a luxury convertible, with the added bonus of headrest adjustability.

As with all G20/G80 generation 3/4 Series, the M4’s interior is a welcome return to form for BMW, from the excellent driving position and superb build quality, to thoughtful switchgear placement, brilliant ventilation and ample storage. And iDrive is probably the best and most intuitive multimedia system out there, too, needing no special skill or distraction once mastered.

A quick note about the instrumentation. The 4 Series design digital readouts are prettier than the standard 3 Series' ugly standard screen that looks ex-Honda Civic. This one offers alternative views and is easy to read at a glance. But it still makes us pine for good old analogue dials. Remember when BMWs were the world leaders in dial design?

Some familiarisation is also required to figure out the M part of the M4, including the various driving and performance modes; they’re divided into Road, Sport and Track settings. Yet, thankfully, they’re all far simpler to get your head round than before, which required too much fiddly concentration, since – once quickly learnt – everything is possible with eyes-on-the-road promptness. A new M Mode button offers pre-determined shortcuts to whichever drive combinations are desired.

The roof is well insulated, meaning that previous-gen folding hardtop-owning prospective buyers shouldn’t be too sad about the fabric above their heads. On the go, front occupants can enjoy a variety of configurations, starting with snug coupe-style cosiness and security, moving to cool pillarless hardtop-style windows-only down cruising, to the full top-down convertible glory. The latter also brings minimal buffeting at speed unless you’re stuck out in the back. Roof-up vision isn't brilliant, though.

Strangely, with the M Carbon bucket seat options ticked, it’s actually easier for some people to get into the back than the front. Pulling a strap sees the front bucket seats (slowly) whir as far forward as possible to allow sufficient room for people to clamber onto the rear seats.

Once sat, it’s clear that longer-legged people will struggle. Knee room is OK (especially if the front occupants are feeling sympathetic by moving their seats forward), there’s surprisingly adequate head room for your 178cm tester when slightly slouched, big feet can be tucked beneath the front seats and scalps never have to touch the rear glass thankfully.

And at least BMW has tried to make life back there comfier for smaller people, due to rear-facing air vents with climate and directional control, two USB-C ports, a pair of cupholders, a centre armrest and some handy storage. The materials are of a high quality construction, too.

However, the fixed back rest is far too upright, the knees-up posture quickly gets tiresome, the cushion is firm and you’re sat on a slight angle pointing outwards. Claustrophobics won't be too happy either. Annoyingly there aren’t side window buttons either, meaning only the driver can lower or raise them. The two-seater back seat is best saved for short trips or kids.

Happily, once the roof is dropped, the hemmed-in feel vanishes, there’s not too much wind intrusion or buffeting with the side windows up and there’s a sense of shared freedom that only a four-seater convertible can bring. Going the full drop-top experience will ruffle more than hairdos at freeway speeds, though. An optional wind deflector can fix that issue for front-seat occupants, but it goes over the back seats, turning the M4 into a two-seater ragtop.

Further back, the 300-litre boot isn’t accessible from the cabin, meaning you can’t put much inside at all. BMW fits a hinged flap that needs to be down for the roof to work since it cordons off the roof storage part of the boot when folded in; when lifted, there’s a useful amount of space for luggage, and it’s a handy rectangular shape instead of an L-shaped slot, but obviously at the cost of convertible driving. You can’t have both.

Note that, compared to the previous folding-hardtop M4, this boot is some 80L larger. 

The Z4 is a convertible, so it’s naturally compromised on space. As far as convertibles go though, you’ll be hard pressed to find one you can fit more stuff into.

The Z4 is wide - the same width, in fact, as a 5 Series - and this carries into the cabin. There are only two seats, but those seats are wide, and occupants will find themselves with luxurious amounts of airspace for their arms, as well as excellent leather-trimmed and padded surfaces for landing elbows on.

Legroom is also great, as the seats have a surprising amount of rail-travel on them, so that even taller folk won’t struggle to fit their limbs in.

A genuinely impressive characteristic of the Z4 is much head room there it is. Despite its low-slung looks from the outside, the roof towers over my 182cm tall head when I’m inside, so this isn’t one of those convertibles that feels like braking too hard might simply decapitate those above six-foot tall.

In terms of storage areas you get some long but shallow trenches in the doors, a bay with connection ports and a Qi wireless charging pad under the air-conditioning controls, a glovebox (hey, not all convertibles have them) and a trick centre console that houses two deep cupholders inside.

There’s also a netted shelf behind the seats that could fit small bags, and given the length of the cabin, you could even fit laptops and the like behind the seats provided you haven’t used the full extent of the seat’s rearward movement.

The boot is deep, wide and long for a drop-top, and offers a total of 281-litres which is more than some popular hatchbacks. It even offers tie-down points and netting either side. To top it off, the fabric roof folds away into its own compartment, so the boot space is unaffected if you choose to drop the lid.

For a convertible – the Z4 is a practicality wizard.

The Z4 isn’t cheap, but it plays in a field of expensive Deutsche drop-tops. Our car was the mid-spec 30i which comes in at an MSRP of $104,900 (before on-road costs).

For that you’ll get a more highly tuned version of the base 20i’s four-cylinder turbocharged engine, producing 190kW/400Nm, 19-inch alloy wheels, M Sport brakes, Adaptive M suspension, and adaptive LED headlights.

That’s on top of the already impressively-specified 20i’s kit which includes dual 10.25-inch screens – one for the multimedia functions, the other as a digital dashboard, a head-up display, full Vernasca leather interior trim, auto-dimming rearview mirror, power adjustable and heated front seats with memory function, dual-zone climate control, 10-speaker 205W stereo, a Qi wireless charging pad, and adaptive cruise control as part of a marginally upgraded safety package (more on that in the safety section).

It’s a pretty plush set of equipment, although a challenging value proposition as the almost-as-well-equipped 20i starts from $84,900, a full $20k cheaper.

Rivals for this 30i model? You’ve got the soon-to-be-discontinued Mercedes-Benz SLC300 ($102,500), all-wheel drive Audi TT S quattro ($105,661), and, at a stretch, the entry-level Porsche Boxster ($122,960).

Of course, being a premium European car, there is an extensive options list. Our car was fitted with the excellent and probably-worth-the-money M Sport differential ($2400), as well as the rudely priced M seat belts (literally just the M pattern embroidered in - $560!) and interior ambient lighting package (lovely, perhaps not worth $550).

The Z4 is only offered in five colours, three of which – including our car’s Black Sapphire – come at a cost of $2000. The red interior, surprisingly, is a no-cost option.

If you’re keeping track that brings the car you’re looking at here to $110,410. Not cheap, and it doesn’t have six-cylinders - but given its other attributes explored later in this review, the fact that it still manages to undercut an entry-level Boxster is actually reasonable.

Here is a summary of Australian-market outputs and prices for the M3 and M4 convertible autos, with the prices in brackets being approximate inflation-adjusted figures for today.

1999 E36: 236kW/350Nm 3.2L in-line six-cylinder engine (I6), $152,000 ($266,000 in 2022); 2003 E46: 252kW/365Nm 3.2L I6, $158,000 ($240,000); 2008 E93: 309kW/400Nm 4.0L V8, $183,442 ($240,000); 2014 F83: 317kW/550Nm 3.0L twin-turbo I6, $178,430 ($202,000).  

In 2022, the G83 M4 Competition lives up to its name in more ways than one, with a 2993cc 3.0-litre double overhead cam direct-injection twin-turbo I6 known as the S58 series, which is itself derived from BMW’s B58 modular family of engines. Its 375kW is delivered at a lofty 6250rpm, while there’s a 650Nm plateau of torque between 2750rpm and 5500rpm.

A kerb weight of 1920kg means the M4’s power to weight ratio is an impressive 195.3kW/tonne, helping its published 0-100km/h time of 3.7s. For a few grand extra, the company will up the top speed by 30km/h, to 280km/h.

BMW says the engine includes cooling and oil supply systems designed for extreme lateral forces at high speeds, while the exhaust uses electrically controlled flaps for a more raucous noise.

Power is channelled to all four wheels continuously via an eight-speed M Steptronic transmission with a trio of shift programs. The AWD system features an active differential to better transmit torque to all four wheels, while drivers can choose one of three, progressively more rear-wheel drive (RWD) biased modes: 4WD, 4WD Sport and 2WD – the latter being a pure RWD set-up.

Other related changes the M4 boasts over regular 4 Series models include special stability and traction control tuning, a double-joint spring strut front axle with unique axle geometry and variable-ratio steering, a five-link rear axle featuring its own kinematics and elastokinematics, M-specific adaptive dampers, a configurable braking set-up according to feel and response, and forged M light-alloy 19-inch alloys up front and 20-inch items out back.

Choosing the AWD-only convertible over the equivalent AWD coupe adds 145kg (and 195kg compared to the RWD coupe), though this is partly offset in two ways over the preceding, folding-hardtop M4 Convertible: firstly, using the soft top drops weight by 80kg; and secondly, while the AWD system does add 50kg, it’s at a lower centre of gravity, thus naturally improving vehicle dynamics.

Which are electrifying, by the way.

Welcome to the age of ridiculously powered four-cylinder turbo engines. Despite a capacity of just 2.0-litres, the engine in the Z4 30i produces a whopping 190kW/400Nm.

That’s probably enough for a car this size. I’m keen to drive the six-cylinder, but surprisingly it seems to offer diminishing returns for extra cylinders offering a 60kW/100Nm power boost for an extra $20,000. Perhaps a six-cylinder is the way to go in a BMW, and given this car’s other seriously sporty attributes, it might be the only way to make it a bit more… fun. More on that in the driving section.

All Z4s are rear-wheel drive, using an eight-speed torque converter automatic. Sorry, no option for a manual this time around.

We managed 12.1 litres per 100km in a mixture of urban, freeway and rural-road driving, including plenty of performance testing. This is a two-tonne M4 convertible capable of supercar speeds, after all. In that context, the economy is more than acceptable. No doubt the stop/start engine function (at idle) helps here.

For the record, the official combined-average claim for this Euro 6-rated BMW is 10.4L/100km, for a carbon dioxide emissions average of 237 grams/km. Thanks to a fuel tank that holds 59 litres of 98 RON premium unleaded petrol, it can manage an average of almost 570km between refills.

It’s claimed that the Z4 will drink just 6.5 litres per 100 kilometres on the official combined cycle test, but I found that sticking my foot in occasionally resulted in a slightly more realistic sounding figure of 8.4L/100km.

That’s still a great fuel consumption number for a car like this, and perhaps one of the strongest benefits of having just four cylinders.

A discerning vehicle, the Z4 will drink nothing less than the best-quality 98RON unleaded to fill its 52-litre tank.

Marvellously.

Earlier, we said that the previous M4 (and some earlier M3 generations) never hit the dizzy heights the best like the E46 managed.

The reason why is bandwidth. Not WiFi bandwidth, but rather the newfound breadth of capability that the G83 model has acquired.

Yes, while even the slowest examples of previous M3s and M4s remained thrilling, with blisteringly potent acceleration accompanied by a soaring exhaust soundtrack, the post-E46 models seemed to become almost too obsessed with the pursuit of performance. Thunderous V8s and twin-turbo V6s are all good and well, especially when they provide explosive responses, but there’s more to sports cars than sheer bloody-minded speed.

More specifically, though the handling and roadholding were outstanding, the previous M4’s steering didn’t feel as connected or one with the driver, instead seeming a little remote and detached. Conversely, even with adaptive dampers on offer, the suspension (on Australian roads) lacked sufficient isolation from bumps and thumps, and so was never settled or calm. It was all too nervous and edgy, like a drug-addled athlete who’s indulged in too much partying.

Thankfully, the curse is broken with the latest iteration, even in the heaviest and slowest version like our M4 Convertible as tested, pushing out boundaries to thrilling effect once more.

With the newly-simplified and logically presented M performance modes only a push of a button away, the driver now no-longer has to concentrate on what setting they’re in, and instead just immerse themselves in the experience of accelerating, steering, cornering, braking and controlling this incredible sports convertible.

Tremendously strong in regular Road mode, the M4’s performance certainly lives up to the legend, stepping up into the supercar realm when Sport or Track are chosen, hunkering down as it thrusts towards the horizon with relentless speed and determination, accompanied by the gorgeous twin-turbo six’s revs as they soar towards the red line. The ultra-alert eight-speed auto’s operation is equally seamless, displaying uncanny intuition in its selection of the right ratio at exactly the right time.

These are all incremental improvements over what has come before. But what’s really changed is how rock-solid the BMW feels as it belts along at speed, magnetised to the motorway regardless of weather, its new AWD engineering keeping everything steady and planted. No more tetchiness to unnerve the driver.

Which makes the feel and fluency of the chassis even more remarkable, given that now all four wheels are driven. The very opposite of leaden or inert, the superbly weighted steering is instead light and alive in your palms, as you carve through corners with pin-point precision. Some might find it a bit too eager to change direction at first, but we reckon BMW has judged the balance just right. Its sheer agility is as life-affirming for driving enthusiasts as it is immersive. Bravo, BMW.

With so much grip and control, this is not to say that the driver can’t hang the M4’s tail out every-which-way, since the chassis set-up allows for progressive oversteer, even in Road mode, along with as much drifting as your courage allows where safe. As with the best sports cars, the M4 is as steerable from the seat of your pants as it is using the throttle.

Finally, there’s the M Adaptive chassis tune, that at long last broadens the M4’s repertoire from motorway grand tourer and rural-road blaster to city slicker and urban warrior, thanks to the suspension’s ability to better-absorb a much wider array of terrible road surfaces. Comfort now lives up to its name, with the ride – though still firm – no longer hard or crashy around town, ushering in a new level of civility that won’t fatigue or aggravate you or your occupants. We're so happy to report this progress.

One area where BMW might want to keep improving, though, is the abundance of road noise intrusion over certain coarse chip bitumen. While easily muffled by the sweet sounds of the twin-turbo six, banging audio system or dropping the roof, it now seems more obvious that the rest of the car has smartened up so much.

A small fly in an otherwise hugely satisfying ointment.

A car that looks this good better live up to the promise behind the wheel, right?

For the most part, the 30i does, but it’s a victim of its own performance credentials and luxuriousness.

See, a drop-top should be fun-packed, you should feel close to the road, connected. Sadly, a combination Z4’s excellent suspension and not-so-excellent SUV-like interior separates you too much from the surface below.

An advantage, of course, is the refinement on offer. The Z4 is easily one of the quietest, most refined convertibles I’ve ever driven, but it’s a little too insulated.

I can’t help but feel like it’s all business and no pleasure. It feels a little more like I should be cruising to work on the autobahn and a little less like I should be flinging it around corners on a tight B-road.

It feels almost wrong to drive it in a T-shirt. It’s serious and doesn’t want you to mess around, it wants you to wear a suit and tie.

This grand-tourer style feel is one that will keep a lot of buyers in the premium space happy, but I’m of the opinion that BMW will have that segment well and truly covered by the new 8 Series. If the budget allows.

Regardless, the 30i’s four-cyl engine feels like any six-cylinder would have a few years ago. It’s got a surge to it in the straights that’s quite satisfying, and it responds via the exhaust with an angry tone that makes it feel a little more alive, especially with the roof down.

This feeling was all helped along by our car’s M active differential which simply won’t let the fat tyres at the rear slide unless you’ve got high-speeds and loads of tarmac to play with – for better or worse.

The Z4 also has ‘variable sport steering’ which reacts to the car’s speed and position of the wheels to adjust the input ratio. It’s good when you’re at speed, but the weight and response of the steering can make the Z4 feel bigger than it actually is at lower speeds. 

The suspension is firm, and can be a little bouncy over rough surfaces, but seems well suited to the Z4’s chassis.

Other than those notable characteristics you’ll find that the Z4 is wonderfully tuned in terms of its inputs, everything is slick and smooth, suited perfectly for long meandering drives.

Convertibles and safety don’t often fall in the same sentence, unless its one where a concerned relative is trying to convince you not to buy one.

In any case, the Z4 benefits from four airbags (dual front and dual side), as well as the expected electronic stability controls. That optional M Sport differential will have the added bonus of preventing any unexpected slip and slide at the rear.

On the active side the Z4 gets ‘Driving Assistant’ which includes forward collision warning (FCW), lane departure warning (LDW), rear cross traffic alert (RCTA), and rear collision warning. The 30i grade also gets 'active cruise control with stop & go' which allows for full auto emergency braking (AEB) with pedestrian and cyclist detection. Not on the spec sheet, but apparently present in the car I drove was some form of traffic sign recognition (TSR) and lane keep assist (LKAS).

A nice high-res reversing camera displayed on the massive touchscreen is a welcome standard addition.

Considering the meagre safety specification of most convertible cars, the Z4 30i shines with a half-way decent active safety suite. But you can forget ISOFIX child-seat anchor points. There aren't any. 

We feel here is where the company drops the ball.

Trailing all of its main luxury car rivals (except Porsche) by two years, BMW only offers a three-year/unlimited kilometre warranty, as well as three years of roadside assistance.

BMW says its vehicles’ servicing is condition-based, depending on how they’re driven and other factors, with a dash warning appearing to let the driver/owner know when it’s time. We advise servicing your M4 annually or at every 10,000km, just to be sure.

No capped-price servicing system is offered. However, as long as the first one is paid for before the first service on a new vehicle, the ‘BMW Service Inclusive Basic packages’ is available at extra cost, covering scheduled servicing for three years/40,000km or five years/80,000km.

No prices are published for M models like the M4, but a normal 4 Series costs from $1800 for the five-year/80.000km package. You can bet an M4’s will cost more.

If recent quotes are anything to go by BMW is set to stick by its lacklustre three-year unlimited kilometre warranty, as it says its customers simply aren’t interested in five years (or longer) when it comes to warranty coverage.

It’s a shame, as even Volkswagen has upped its warranty to five years, and Mercedes has considered a 10-year coverage plan in the past.

In terms of servicing, there are two fixed-price plans available – the suspiciously cheap ‘Basic’ plan which comes at a cost of $1373 for five years (or $274.60 per year) and the more realistic-sounding ‘Plus’ which costs $3934 over five years (or $786.80 per year).

Like every other BMW, the Z4’s computer tells you when its service time: how often it needs maintenance will depend on how often – and how hard – you drive it.