BMW i Series vs Mercedes-Benz AMG GT

What's the difference?

The BMW iX3 is a rarity in the market, a premium-feeling electric model that's not a whole lot dearer than petrol alternatives.

For those happy to trade some of the Tesla Model 3 and Kia EV6 GT's all-paw performance for a luxurious cabin, slick drive and badge cachet, the iX3 M Sport is a very attractive package. Until Audi's Q4 and Q6 e-tron arrive, the iX3 remains basically peerless in this part of the market.

No wonder, then, that BMW is Australia's third most popular electric car brand after Tesla and BYD. The vehicles capture everything the brand promises at a price that looks good on paper and better in the real world.

The GT63 4Matic+ is a breathtaking example of everything that Mercedes-Benz and AMG are.

Ferociously fast, incredibly agile and superbly sophisticated, it should be on anybody’s shortlist, if that also includes a Porsche, Aston Martin, Maserati or even a Lamborghini. And it’s definitely much more than yesterday’s SLC ever was – for similar money in today’s terms, as it turns out.

But, around Tasmania’s glorious roads at least, the Mercedes-AMG lacks the ride comfort and road noise isolation to be a fully-rounded-out GT, and that’s a disappointment for a brand with such formidable history in making such cars.

Now that we've seen the new X3, the current model is already dated. Not that it was a cutting-edge design at launch but there is precious little offensive about this mid-size SUV.

Fussy wheel designs, strange closed in grilles and clashing blue accents aside the iX3 M Sport remains a plenty handsome option as you approach.

Inside the cabin's shapes feel positively conservative next to BMW's latest efforts like the X2 and 7 Series but, in a way, this is no bad thing.

It's also nice that you can tailor this car's appearance to your liking without spending extra, the combination here rocks a nice blue paint with tasteful brown upholstery for a classy look.

You can have Oyster white leather or simple black and the paint colour palette is refined without being restrictive.

This is still clearly a Mercedes AMG GT coupe, like the 2014 C190 original, but a ground-up redesign sees it subtly yet significantly altered.

Some 270kg heavier than before, the larger-in-every-dimension body combines aluminium, steel, magnesium and fibre composite materials for improved rigidity and a lower centre of gravity. Length (4729mm) and wheelbase (2700mm) have been stretched by 177mm and 70mm respectively. Width (1984mm) and height (1352mm) are also up.

The nose treatment is similar to before, especially with the bulgy bonnet and signature vertical slatted grille fitted. These, combined with the LED digital headlight shape effect, is reminiscent of, but far-better executed than, the goofy-looking MG5’s face.

Underneath, it's an all-new platform shared with the SL, with the rear transaxle of the old car replaced by a permanent AWD system, leading from 46:54 front/rear weight distribution to 50:50 as a result.

That aggressive, exaggerated cab-backward/ultra-long bonnet silhouette that visually connected it with the SLS gives way to more-conventional and practical coupe proportions that is striking if not especially original, since they do look quite 911-esque. Along with the longer wheelbase and wider tracks, the result allows for two small rear seats to be fitted, while liftback cargo access remains.

Similarly, in the name of way-more usable interior packaging, Mercedes-AMG says it pushed the driving position nearly 180mm forward compared to the previous GT. Let’s see what that all looks like inside.

The BMW X3 was developed with family buyers in mind and that has paid dividends because it has an extremely practical cabin with lots of thoughtful storage.

Each of the four doors has a bottle holder and generously-sized pocked for extra storage. There are two cup-holders in the centre with a wireless charging pad, secure spot for the key fob and USB port in easy reach. You can slide a roller cover down to hide valuables.

Key driving controls are smartly grouped together around the iX3's unconventional gear selector. Here, you'll find the start/stop button along with hard switches for drive mode selection, stability control and exterior cameras.

Right next door is where the rotary 'iDrive' controller lives with yet more physical shortcut buttons. Including the extra option to easily interact with the multimedia system on the move is a refreshing delight that you don't see in so many touchscreen-heavy EVs. There's also a physical stack for HVAC and seat heating controls.

The 12.3-inch touchscreen is responsive and bright with BMW's slightly older system having a more conventional appearance than the latest software in the iX2. Apple CarPlay and Android Auto are wireless and still work flawlessly.

If there are some negatives, they would be some build-quality niggles. On the whole the materials are high quality and the car is well screwed together but the indicator stalks feel decidedly flimsy compared to BMWs of old and I noticed a rattle from the parcel shelf on the road.

The eight-way power adjust seats with tilt and under-leg extension are classic BMW, being sporty enough to hold you in but with enough padding to stay comfy. Though we will knock this car down for lacking power lumbar adjust.

Those in the back will be plenty comfortable even if they're taller than 180cm with ample head, leg and toe-room. There doesn't appear to be a major compromise to the floor height despite BMW stacking 10 lithium-ion modules beneath.

Vision out is excellent with an expansive glasshouse and full-length sunroof.

Amenities include two USB-C charge points, a third climate zone, fold-out armrest with pop-up cup holders and generous storage in the doors.

Fitting child seats should be pretty simple with doors that open wide, two sets of ISOFIX ports (that you can't lose the covers of) and three prominent top tether anchors in the recline-adjustable backrest.

The boot is large with 510L of space at a minimum that expands to 1560L if you fold the 40/20/40 split backrest flat. There's a sense of solidity in that process, too, with sturdy levers and components.

So sturdy that the retractable luggage cover is quite difficult to remove, especially for shorter owners. Other niceties include a single shopping bag hook, LED lighting and 12-volt socket in the back.

No BMW X3 comes with a spare tyre so that should come as no surprise. The iX3 instead has a tyre repair kit. There is underfloor storage in the iX3, though, which is the perfect place to store both charging cables — Mode 2 and 3 — that are included.

The first impression inside is that of space, despite the falling roofline and coupe-like upsweep of the side windows and you look back. While, again, similar to a 911s, a kink at the door gives the GT a unique character.

Even larger people will appreciate the generous amounts of room up front, with space to stretch, sat in sumptuously comfy bucket seats. Note that the standard ones are better than the racier but firmer Sports versions.

The driving position is perfect, ahead of a dashboard that is very typical modern Mercedes in appearance and layout.

To that end, the tablet-style integrated touchscreen (11.9 inches) is clear, fast and intuitive once time is taken to learn it. And points are also won for the multi-configurable electronic instrumentation, that allows for a variety of screens, including track, classic and minimalist views.

The trademark turbine air vents, the quite beautiful material and trim finishes and just the general solid feel are further typical contemporary Mercedes cabin treatments, as are the excellent ventilation and ample storage options.

And while rear vision isn't great, that's what cameras are for. It's all pretty much on brand.

It is a shame, given how elevated the Mercedes-AMG engineering is underneath, that the GT’s interior look and ambience is so similar to those of a (albeit higher-spec) C-Class or GLE. It's simply not as special as some of the company’s previous sports cars.

More annoyingly, the ride is too firm and bumpy for a GT, and this has the unhappy effect of provoking random rattly trim sounds within the cabin. It’s a bit like scrunched-up cellophane. In a $420K (as tested) Merc, that’s very disappointing, especially as it can be heard over the copious amount of road and tyre noise droning through, particularly on coarser bitumen surfaces.

Further back, the rear seat is strictly two-plus-two, and nobody over 150cm tall is recommended to travel there by Mercedes itself. That sloping roofline is the culprit. That said, brief trips with a bowed head are possible, as the fixed cushions and split-folding backrests are actually surprisingly comfy. But only for short journeys. Kids should love it though, and the second row does open up the GT’s usefulness enormously.

As does a near-doubling of the AMG’s cargo capacity, jumping 146 litres to 321L with backrests erect, to a whopping 675L (+325L) in two-seater mode. The flat floor is accessed via a large electrically-operated liftback door, offering quite a large aperture for easy loading/unloading.

Having no spare wheel helps here, with a tyre inflation kit included in lieu of that.

Meanwhile, at the front, under the bonnet, things have definitely changed for the better as well.

Starting from $370,400 (all prices are before on-road costs), the Mercedes-AMG GT63 4Matic+ is priced and positioned as something of an eagle amongst some pretty delectable doves, given its combination of four seats, 430kW of power, 800Nm of torque and four-wheel drive.

No rival equivalents can match the Mercedes on paper. The 398kW/610Nm 911 Carrera 4 GTS T-Hybrid offers less power but starts from $400,000-plus. The 410kW/650Nm GranTurismo Trofeo begins at $450K, the 500kW/800Nm DB12 from $455K and the 404kW/470Nm Continental GT from $460K.

Only the 460kW/750Nm BMW M8 Competition comes closest to the Mercedes-AMG, from $380K.

Side note, today’s GT is only slightly more expensive than what the 450SLC was nearly half a century ago when adjusted for inflation.

And, just like with that classic old Benz, it shares much with the brand’s legendary SL convertible stablemate – including, in this case, standard all-wheel drive and active rear-axle steering… aka 4WS to select third and fourth-generation Honda Prelude owners out there.

What else does $400K-plus buy you? As you’d expect, the GT63 4Matic+ comes choc-full of standard equipment, much of it typical of the luxury coupe breed, with leather-covered and electrically operated everything.

How about a front-axle lift system with GPS-enabled memory that automatically raises the GT’s nose to help clear bumps and then remembers to do so next time?

There are climate-controlled AMG sports seats with inflatable bolstering and massaging functionality, a fixed glass roof, a head-up display, augmented-reality satellite navigation, 360-degree surround views, performance telemetry data as part of an extensive multimedia system, an 11.9-inch portrait touchscreen, 11-speaker Burmester audio, a handsfree-powered tailgate, 21-inch alloys and cutting-edge driver-assist safety tech. More on that in the Safety section below.

Then there are the myriad option packs, bumping the GT63’s price up towards $500,000. These include a $2.7K seat trim package; a $10K AMG Night Package that adds darker trim treatments (often where chrome was); an aerodynamics package with fixed spoiler replacing the standard active spoiler; a $2.6K AMG Performance Seat package; a $13K Carbon Fibre package and $13.2K Ceramic Brakes.

Now, while the new GT does ditch the previous model’s unique rear transaxle spaceframe pioneered by the gull-winged SLS of the early 2010s, the resulting longer wheelbase and shorter overhangs do provide less outlandish and more practical design.

Let’s check that out in more detail. 

In this case there isn't much under the bonnet except for electric gubbins. The single electric motor – that uses no rare earth materials – resides at the back and generates 210kW/400Nm.

Those outputs are fairly close to a petrol X3 30i, though of course this model is rear-drive only.

Thanks to the rapid response of electric motors, the iX3 M Sport can sprint from 0-100km/h in 6.8 seconds (claimed).

BMW has chosen to give the iX3 a long-travel progressive throttle pedal that makes grunt easy to meter out. However, the regenerative braking could do with a little more refinement.

There are two settings, 'D' — just like letting off the throttle in a combustion car — and 'B' which is quite strong. The blending between regenerative and physical caliper-on-rotor braking is vague, though, which can make low-speed moves a bit jerky.

There’s a plaque signifying which engineer “handcrafted” the GT’s engine – in this case, the famous M177 in 3982cc, 4.0-litre twin-turbo intercooled V8 petrol guise.

Delivering 430kW of power at 6500rpm and 800Nm of torque from 2500-4500rpm, it sends drive to all four wheels via a nine-speed multi-clutch transmission (dubbed MCT in AMG-speak), catapulting the GT63 4Matic+ from 0-100km/h in just 3.2 seconds, on the way to a top speed of 315km/h.

How does it do that?

With AWD, the GT is now nearly 15 per cent heavier than before, but it still manages a punchy 218kW/tonne. Active aerodynamics over, inside and under a more-rigid body structure also helps.

The AMG 4Matic+ AWD system goes from 50/50 front/rear, to 100 per cent rear, variable torque distribution according to conditions and settings, and backed up by an electronic limited-slip differential. Among the many driving settings are Race Start, Drift Mode and good-old Comfort, if it all becomes too much.

Also keeping all that performance in check is a high-performance composite brake setup with improved cooling for faster responses.

Interlinked active roll bars improve body control, the five-link independent suspension features adaptive dampers for a softer ride.

And, as for that 4WS tech, the rear wheels steer opposite to the fronts at up to 100km/h (by some 2.5 degrees) for tighter and tidier handling, or 0.7 degrees in the same direction above 100, for greater stability and road-holding.

Its effect on the way this near-two-tonne coupe zigs and zags around corners is something you need to experience to really appreciate.

The iX3 M Sport's WLTP rating is a respectable but not groundbreaking 461km on the combined cycle. The reality is a little bleaker, our test car displaying 316km on its digital instruments at 100 per cent charge.

Going against what you might expect for an electric car, the iX3 was not very efficient in town, we initially saw 24kWh/100km on the read-out which is quite high.

It is better suited to a longer, steady-state run. Our regular 200km country and suburban test loop dropped the consumption to 18kWh/100km for a real-world driving range of 411km.

When it's time to bring the charge levels back up the iX3 will take on AC electricity at 11kW, for flat to full in seven and a half hours.

Public fast-charging caps out at 150kW (DC) though averages to 104kW over a 10-80 per cent session. This should take 21 minutes, says BMW.

We only observed a maximum of 101kW on a DC charger though the pylon did not appear to be performing at full energy with other vehicles having similar issues.

Actually, the GT’s economy isn’t horrendous considering how fast it can go.

Even blasting a few times around beckoning country roads, we managed an indicated 13.0L/100km, which is an improvement on what Mercedes-AMG says the GT averages the 14.6L/100km average that Mercedes-AMG officially states.

That translates to a carbon dioxide emissions rating of 334g/km.

Using 98 RON premium unleaded petrol, an average of just under 480km between refills of the 70L tank is possible. The urban run sees consumption rocket to 21.8L/100km (for just 321km of range), or 10.4 out on the highway run, meaning that over 670km is possible should you decide to drive in a docile manner.

Despite no saucy straight-six, V8 or twin-cam four-cylinder there is an inherent 'BMW-ness' in the iX3 M Sport. The way it steers, accelerates and rides all match the brand's DNA.

It is not a plush SUV, with some firmness to the suspension even in Comfort mode on the adaptive dampers — this may have something to do with BMW's 40PSI front and 45PSI rear tyre pressure recommendations — but without ever being crashy.

Build up a little more speed, beyond 60km/h for example, and the body settles nicely with a solid, assured stance.

There's no evidence of suspension noise and road noise is very well insulated as well, even without the up-spec M Sport Pro's acoustically insulated glass. 

The steering is light in Comfort mode which makes it ideal for urban driving. It also has three turns lock-to-lock which is a lot for a sporty-ish BMW, however that is largely down to the improved steering angle. Without an engine or AWD system, the iX3 has a great turning circle of just 12.1 metres.

Moving things up a notch into Sport adds extra weight to the steering which helps judge the grip on good roads, which is pretty decent from the 245/45R19 Yokohama Advan Sport V107 tyres.

When you approach the limit, the iX3 is very secure but significant mid-corner bumps can unsettle the car, bringing its 2180kg tare weight (a 325kg penalty over the xDrive20i) sharply into focus. Pull it back a touch, though, and the iX3 M Sport is plenty rewarding on a country road.

Mostly, the iX3 is a refreshingly natural electric car out on the road. You could put anyone in the driver's seat and they'd be smooth just like in a combustion car.

Nobody will drive the GT63 4Matic+ and think, ‘Oh, this is OK’, because its breadth of performance is phenomenal.

No matter which mode you're in, from Comfort through to track-tuned Race, the Mercedes-AMG blends forceful pace and commanding control without ever breaking a sweat.

Flex your right foot and the two-tonne coupe bounds into action like a giant on a mission, striding past posted speed limit signs in nanoseconds and way, way faster than the law will stand if diligence isn’t exercised.

And there’s no point relying on seat-of-your-pants sensations, either, because the chassis below embraces the road with an almost zealous devotion. Which is astounding, given how agile the four-wheel steering-enhanced handling is.

The 63’s super power is exactly that – it dulls your sense of speed. One tester admitted to exceeding 150km/h before noticing. An odd confession considering the sonic boombox that is the bi-turbo V8’s howl.

But jailbait performance is not even the 63’s most lingering joy. That would be its steering perfection, that delivers that rare trifecta of keenness, crispness and communication. The wheel feels eager and alive in your hands, even when powering between tight turns, backed up by sensational grip and control. How can a two-tonne GT handle so sharply?

Warm, dry roads were the order of the day, so we can’t tell you how the 4Matic+ permanent AWD system deals with wet or slippery surfaces, but the slick multi-clutch transmission, seamless torque-vectoring tech and sticky tyres more than cope with the 63’s formidable outputs.

So, that's the gushing part out the way, then.

Despite the adaptive dampers, rigid architecture and exquisitely sophisticated suspension, the ride is simply too stiff in Comfort mode, and downright jittery on some of the Tasmanian roads we tested on, for the 63 to be considered a true luxury grand tourer. It just isn't comfortable, luxurious or supple enough.

Plus, grippy as they are, the 21-inch wheels transmit too much road and tyre noise through to the cabin, meaning that the GT isn't as quiet as you'd hope. Add the aforementioned trim squeaks, and the expected cocooned silence isn’t always there.

The upshot is that the 63 possesses more of a sports car character than a luxury GT character. Great news if you're a 911 type buyer and are seeking a high-performance 2+2 alternative, but a disappointment if comfort and refinement are priorities.

Still, it is impossible not to be deeply moved by this Mercedes-AMG.

While the GT doesn’t score an ANCAP rating – probably because it’s too expensive to crash test – we’d wager that it would be above-average, given Benz’s track record as a pioneer in this field.

That’d due to the scores of active, passive and driver-assist safety features fitted, from multi-faceted autonomous emergency braking (AEB) and lane-support systems to Mercedes’ PRE-SAFE tech that anticipates a crash and then prepares the car for impact.

More specifically, the GT includes Active Lane Change/Keep Assist, adaptive high beam as part of its megapixel LED set-up, adaptive cruise control, Cross-Traffic Assist, Evasive manoeuvre support, an emergency services call-out system, 360-degree camera views, pedestrian protection bonnet and eight airbags.

In other Mercedes products of today, AEB operating parameters are 7-80km/h for vulnerable road users like pedestrians and cyclists, and from 7-250km/h for vehicle-to-vehicle, while the lane-keep support systems operate between 60-200km/h.

Finally, there are ISOFIX child-seat anchorages in the front passenger seat and two in the rear seats.

The iX3 M Sport is now covered by a five-year/unlimited kilometre warranty in Australia.

Servicing is due on a conditional basis with the multimedia system prompting the owner when to visit a dealer.

BMW offers serviced packages for electric vehicles that last six years/unlimited kilometres, with the iX3's pack costing a reasonable $2325 over that time.

What’s the GT like to own?

Mercedes-Benz offers a five-year/unlimited km warranty, with five years of roadside assistance. This is average for most mainstream and luxury brands, but superior to most sports-car makers like Porsche and Lamborghini.

Intervals are every 12 months or 20,000km, and while no capped-priced servicing is offered on the GT, pre-paid three-, four- or five-year service plans are available, ranging from $5165, $7700 and $8665 respectively.

Big performance demands big maintenance bills, it seems.