BMW M240I vs Mercedes-Benz SL-Class

What's the difference?

When BMW is on a roll, the world needs to watch out.

And, as our Thundernight metallic-hued M240i so literally demonstrates, its purple patch continues after a string of modern marvels like the latest 4 Series and iX, distilling the essence of compact sports coupe and luxury cruiser with dizzying confidence.

Joining the pantheon of back-catalogue greats like the 2002ti and 330Ci, we're missing it already now that the keys have been returned. Isn't that the true sign of the quintessential BMW experience?

The SL's overall score is somewhat skewed by everyday concerns, and rules are rules - an average punter will find the price of this car somewhat confusing and the devil-may-care attitude to fuel consumption bewildering.

If neither of these things are a problem, then the SL63 makes plenty of - well, not sense, because it's not a particularly clever or considered car - but it fills a niche that not so long ago we all thought would go the way of the dodo.

The fact it sells so few examples is betrayed by some of the cabin amenities and the fact that Mercedes hasn't put much effort into reducing the car's weight to improve its consumption or sharpen up the handling.

The fact it still exists at all is pretty damn cool, though, and for certain people an SL63 purchase is the culmination of a lot of hard work.

If it is your dream car, the SL63 won't disappoint. Everyone who rode with me said it was mightily impressive, but you've got to really want it. When you're not far off buying a Ferrari California T or Aston Martin V12 Vantage S for the money, you'll need a real yearning for the three-pointed star to go this way. And if you do, good luck to you - you've probably worked quite hard to get here.

What is happening with BMW design? It's as if the Germans have run out of ideas.

Though we're eternally grateful it exists, the G42 is the least pretty of the three 1 and 2 Series coupe generations, as well as the most aggressively styled. All the usual macho tropes are present – cab-backward long-bonnet/short boot silhouette with an exaggerated dash-to-axle ratio, huge front air intakes, bulging bonnet and diffuser-heavy rear end.

There's also a beady eyed look to this M240i, with its squinty headlights and angry tail-light shapes further piling on the attitude. It's a far cry from the simple elegance of the E82 original, let alone the classic E30 of the Eighties. We wonder how much extra the M2 version will be when it surfaces later on.

That said, the G42's design is in keeping with something wearing an M-something-something prefix. In the optional purple of our press car, it certainly turns heads. That said, in the Bangle era, BMWs didn't have to rely on paint to do that.

Bangle, by the way, refers to BMW's late '90s/early '00s head designer Chris Bangle, an American with a bold aesthetic, scant regard for tradition and a taste for the controversial. His effect on vehicle styling, starting with the 2001 7 Series, is still felt today.

Dimensionally speaking, comparing the length/width/height/wheelbase measurements of the M240i (4548mm/1838mm/1404mm/2741mm) with a 2000 E46 330Ci (4488mm/1757mm/1369mm/2725mm) shows how today's coupe is palpably larger.

Over the previous (F22) 2 Series, the newcomer is 105mm longer, 64mm wider and 28mm lower; the wheelbase has been stretched by 51mm, while the front and rear tracks are 63mm and 35mm further out, respectively. Result? More space inside for today's lucky occupants.

The SL has always been completely unapologetic about its size and seems to be designed to accentuate rather than hide its length and width. The long bonnet screams power and prestige, and get out of my way, and is reminiscent of the little-loved McLaren SLR project of some years ago.

The size of the Mercedes logo on the huge front grille leaves you in little doubt about the brand of car that’s about to pass you at speed and some might say (okay, I would) that its large surface area is a little vulgar.

Like the SLR, the design doesn't seem to have a particularly cohesive strategy, with a number of Mercedes elements from around the traps that climb over each other. Roof up it looks awkward because of the gigantic posterior while with the roof down it looks overly long and, again, tail-heavy.

Folding hardtops are notoriously cumbersome and need a lot of room to hide them, but the silent operation is something to behold.

Elements that are worth deleting if possible are the dodgy 'Biturbo' badges. It's that kind of bling that gets people raising their little finger at you.

Interior dimensions may not be paramount to most coupe purchasers, but a stylish one with quality fittings and generous equipment levels certainly is, and here the M240i is bang-on brand.

For a compact two door, the M240i is pleasingly accessible. Long doors and a tallish roof help entry/egress, into a 2+2 cabin that obviously prioritises front-seat occupants. And it does that exceedingly well.

There's space to stretch – even if you're two metres tall – up front, as long as the rear seats aren't occupied, as a result of generous leg and shoulder room, while headroom should also be sufficient, even with the sunroof fitted. We're talking about a small coupe, remember, so that's impressive.

Vision out isn't as bad as you might imagine, either, due to the airiness that the elongated side windows provide. There are blind spots, though, with the B-pillar being the worst, but at least the extensive camera and sensor network surrounding the car provide reassuring back-up.

The handsome M Sport front seat option ($2000 extra) look like they mean business, providing all the comfort, support and adjustment most occupants will ever need. They're firm enough when you need them yet restfully supple all the time. Backed up by a multitude of electronics, both buckets will brace people of pretty much all sizes, while the driver has the luxury of two memory settings that also take in mirror positions.

Remember how the new 2 Series comes via Mexico? You'd never know it wasn't built in Germany, from the solid build quality and expensive materials to the extremely welcome absence of squeaks and rattles. No area exposed to the occupants looks or feels cheap.

Also meeting expectations is the dashboard itself, which is essentially a scaled-down replica of every recently released BMW – futuristic and fabulous iX aside – since the current (G20) 3 Series in 2018 broke the Bangle-era curse of disappointing new-millennial models.

If you're hoping for a return to classic analogue instrument dials, forget it. The M240i's instruments are modish electronic items, providing plenty of vehicle and driving data, and supported by an excellent head-up display. Like the switches and buttons, they're easy to fathom, with little familiarisation required.

As we've said repeatedly in other BMW reviews, the iDrive multimedia controller is amongst the best in the business, responding instantly to inputs. The other basics – ventilation, storage, driving position – are also first class. Nothing to complain about here. The company is on a good thing and it's sticking with it.

Accessing the rear seats is aided by electrified front seats that slowly whir forward, to provide a big-enough aperture for your medium-build 178cm tall tester to squeeze in.

Once sat, with legs splayed apart, there's just enough space for another person of similar height and proportions, as well as surprisingly decent levels of vision thanks to the narrow front bucket seats and extended rear glass area, to offset any feelings of claustrophobia.

BMW has also provided several welcome amenities, including face-pointed rear vents with full single-zone temperature control to serve two occupants back there, armrests (with the centre fold-down item also packing in a pair of cupholders), reading lights and coat hooks.

Sadly, however, the rear windows do not retract, and the thick door pillars are fixed, so you cannot enjoy a pillarless hardtop experience. That's what the M4 coupe (and convertible too) is for.

While rear-seat space is adequate, with enough room for shoulders, thighs and feet if the front-seat occupants don't mind raising the cushion a little, the backrest is too upright to be considered comfortable on longer journeys. At least the low cushion is scalloped enough to provide some support, though, again, not over extended periods.

That rear backrest folds, by the way, to a 40/20/40 split, providing access into the 390-litre boot while still able to accommodate a single passenger. The lid opens up and wide, offering up a long, flat and wide space for storage. Along with a 12V outlet and tie-down hooks, you'll find a tyre-repair kit, since no spare wheel is carried.

“Practicality” is about as relevant to this car as a code of ethics is to a drug dealer or a contract killer, because the SL63 buyer is hardly worried about cupholders and boot space. For what it's worth, there are four cupholders in the two-seater cabin (which might explain why owners aren't worried about their liquid carrying prospects) and a minimum boot space of 364 litres and a maximum - with roof up - of 504, which is actually not bad.

Cleverly, there's a little robot-operated luggage cover inside the deep boot that stops your gear from being crushed when the roof goes down.

There's also space in the long doors where you might secrete a bottle of wine that would get a NSW Premier fired if he thanks you for it, and a bin in the console to hide your phone.

It’s difficult to ponder the idea of value when a car is already approaching $400,000 at a rapid rate even before you start piling on the options. On the plus side, for a list price of $368,715 you do get an extremely long list of standard equipment.

The SL has always been completely unapologetic about its size.

Edited highlights include leather on almost every available surface, heated and cooled electric seats with a fan heater for your neck, a B&O stereo that will shatter the windscreen on request, aluminium trim that's real aluminium (mostly), Active Ride suspension, sat nav, dual-zone climate control, active cruise, LED headlights and a huge swag of safety gear.

The 12-speaker stereo also has DVD, limited smartphone integration via Mercedes' COMAND system, a seven-inch screen and, of course, Bluetooth.

As with all of our current favourite BMWs that aren't electric on full-fledged M cars, the M240i is fitted with a variation of the divine B58 engine – a 2998cc 3.0-litre double overhead cam direct-injection turbo I6. It delivers 285kW at a heady 6500rpm, and 500Nm of torque between a low 1900rpm and 5000rpm.

A kerb weight of 1690kg (200kg more than the 220i equivalent) means the M240i's power to weight ratio is about 169kW/tonne, which may explain why it can manage the 0-100km/h time in 4.3 seconds. V-max is 250km/h.

Power is channelled to all four wheels continuously via an eight-speed M Steptronic transmission, while the AWD system features a differential to help transmit torque to all four wheels more cleanly.

Controlling all those outputs, the M240i's suspension consists of a two-joint spring strut front and a five‑link rear axle arrangement, with M Sport suspension including variable sport steering, additional front axle struts, M Sport brakes, M Sport differential at the rear axle and adaptive M suspension with electronically controlled dampers.

The SL63 is powered by Mercedes’ increasingly famous V8, with two turbos along for the ride to add oomph and cut the car's famous consumption, at least slightly. The 5.5-litre unit produces a massive 430kW and a scarcely believable 900Nm of torque.

All of that heads rearward via a seven-speed dual-clutch transmission that helps sling the 4.6m, 1848kg machine to 100km/h in 4.1 seconds.

Over exactly 503km of city, suburban, freeway and performance testing, we managed a credible 9.6 litres per 100km – and that was with the air-con on  constantly and regular visits to the 7000rpm rev limiter. No horses were spared in our quest to properly assess this vehicle.

BMW's official combined-average claim for the Euro 6d-rated M240 is 8.0L/100km flat – and 6.6L and 10.3L in the Extra Urban and Urban runs – for a carbon dioxide emissions average of 185 grams/km.

The small fuel tank swallows just 52 litres of E10, 95 or 98 RON (as tested) premium unleaded petrol, meaning an average of 650km between refills is possible.

Much as is the case with the price, there's no real way to soften the blow here - the SL63 drinks like a footballer on Mad Monday, except it does it every day. The official combined cycle figure of 10.2L/100km is quite easy to double, as we did, averaging 21L/100km in mostly flowing suburban traffic. In the car’s defence, the accelerator pedal spent a good deal of time near the firewall.

The SL does have stop-start to help reduce its considerable environmental impact.

In a word, invigorating.

Stuffing a big old engine in a little-ish car is always an exciting recipe for thrills, and the M240i Coupe does not disappoint.

Press the start button, and the sublime B58 3.0-litre turbo I6 growls into life, setting a rich tone for the level of performance as well as sophistication that's coming.

Even in Eco mode, off-the-line acceleration is stirring, with a hefty shove if you're in a hurry, or a brisk pace if you just long to just take it easy, defined by smooth upshifts from what remains one of the world's greatest-ever automatic transmissions.

That said, Normal is the default operating setting, and here the M240i can take on a Jekyll and Hyde split-personality, that goes well beyond simply possessing a strong throttle response accompanied by a soaring exhaust note. The engine sings sweetly even right up to 7000rpm, while the gearbox is uncanny in its ability to always be in the correct gear, yet will simultaneously hold each ratio in manual mode (via the shifter or paddles) if the driver needs to go hell-for-leather.

Speaking of which, in Sport mode, the 3.0-litre turbo goes into red alert, taking on a louder and more muscular mood, as it roars along with frenetic yet effortless speed. What seems like 90km/h can, in fact, be very much more, and with plenty of extra oomph in reserve.

It's so typical BMW that purists affronted by some of the brand's other niche offerings of late will cry with joy that the art of making a sports coupe has not been lost in Bavaria after all.

And that's before the first turn of that fat little steering wheel. Here the 2 Series Coupe's 3 Series-derived CLAR architecture's DNA is immediately obvious, providing subtle balance and an immersive connection to go with all that bolshy brawn.

The M240i will glide along precisely where pointed, sticking steadfast to the tarmac while cornering at speed without breaking a sweat. That mechanical rear diff helps provide both alacrity and reassuring control. Yes, it remains weighty and planted when punted relentlessly through tight corners, but it's also not as heavy-feeling as before.

Being AWD, there's grip galore to rely on for security, yet the M240i still seems deliberately rear-drive biased in its set-up, so the driver can hang the tail out if wanted with gradual ease in Normal, or with a little more of a sideways flick in Sport. The modes are configurable so the level of engine, steering and suspension responses can be tailored as desired, meaning that in the racy Sport Plus setting, with stability and traction controls on hold, the full oversteer experience is possible if you're game/brave/silly enough.

This car's brilliant performance is also down to incredibly dependable and nuanced braking, adding another layer of driver enjoyment, since it can pull up hard and fast if need be without drama or fuss.

So, it's no surprise to learn that an M-Sport-enhanced BMW can be a deliciously fast and limber along a mountain road.

But the real progress over the old F22 is just how suave and polished the G42 is if you're tired and stressed, isolating its occupants from the rigours of rubbish road surfaces. Kudos to the 'Adaptive M Suspension' and its adaptive dampers for this, for they're standard M240i fare. The resulting cushy ride completely broadens the dynamic bandwidth of this compact sports coupe, making it an everyday commuting proposition.

Ultimately, it's a bit of a struggle to find fault in the 2 Series' drivability and dynamic make-up. The usual Euro luxury car bugbear of too much coarse-chip tyre noise applies, but as this is a sports coupe, that's not such a big deal here. Even wind noise levels are subdued – all the better to drink in that glorious turbo engine wail.

BMW, you got the M240i delightfully right.

There are a number of impressive things about the way the SL drives. Firstly, astronauts will be familiar with the galactic thrust of the V8. It seems endless, seamless and ready to sling the big coupe into the outer atmosphere. Few engines of any kind can match the relentless go on offer in the SL and much of the credit should go to the seven-speed twin-clutch transmission.

When you jump on the brakes and shift down, the exhaust keeps the show going with angry crackles and pops.

Containing a torque figure like the twin-turbo V8's requires a lot of electro-trickery to stop you from being launched off the road. The great thing about all that stuff is that it works unobtrusively and smoothly.

Mashing the carpet in an SL without traction control would create much sound and smoke but little forward progress, such is the twist on tap. The SL has a range of modes from full-nanny (which is meant to keep you on the slippery Alpine road you've chosen to get you to some Swiss ski resort) while turning the dial all the way around to Race loosens the bonds.

It's in this mode you'll have the most fun and it does seem that the intermediate settings are a bit of a waste of time. Race mode does little to diminish the amazing ride quality provided by the active suspension setup, but relaxes the reins on the huge rear tyres. Exiting roundabouts is suddenly a huge laugh, with the tail cheerfully breaking traction and the two-mode exhaust thundering in a most pleasant way.

Better still is that when you jump on the brakes and shift down, the exhaust keeps the show going with angry crackles and pops, with more on the way when you lift off. There's little to match the aural pleasures of a properly tuned V8 and Mercedes has resisted the temptation to quieten it down on the outside and generate a fake noise for the inside. Although that would be stupid in a convertible, if you think about it.

The SL63, despite its AMG badge, isn't about all-out handling, of course. The Ferrari California would definitely show it how it’s done on a winding country road. The SL is more about flow, building momentum and rarely shifting down to second gear. The monstrous torque is enough to keep things rolling but should you wish for a bit more of the exhaust bellow, second is there for the taking.

Hustling the big convertible feels wrong, not because it can't do it, but because it's not really what it's for. Having said that, it offers a kind of fun that nothing else on Earth will provide, not even a Bentley GTC.

With the roof up, the SL63 is a quiet place but not remarkably so. The huge sticky tyres do the cabin's hush no favours, with an annoying roar on a wider range of surfaces than you might expect.

Roof down, it's hardly a paragon of virtue. A lot of wind noise reaches the cabin, even well below the huge speeds the SL can reach. So if you want to talk, it's windows up you'll need to deploy the mesh screen that bridges the roll hoops.

Six airbags, ABS, stability and traction controls, blind-spot sensor, lane-departure warning, brake assist, active safety bonnet, lane-keep assist, driver attention detection, AEB.

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

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. A 2 Series should cost from $1700 for the five-year/80.000km package.

The SL63 is covered by Mercedes' three-year/unlimited kilometre warranty. And, er, that's it.