What is it?
It's the M6 Gran Coupe. Which makes it, depending on your perspective, either an M5 with a squished roofline, or an M6 with a couple of extra doors bolted on.
BMW, however, would like you to think of the M6 GC as something else entirely: no less than ‘the most exclusive way to experience BMW'. Company chiefs refer to it as the M-Division's ‘absolute flagship'.
Certainly the GC's price justifies those 'flagship' claims: at £97,490, it weighs in some £15,000 more expensive than the bigger, more practical M5 saloon.
See more pics of the BMW M6 Gran Coupe
So let me guess: 500-and-something bhp twin-turbo V8, seven-speed DSG, rear-wheel drive?
Indeed. The GC's mechanical recipe is all but identical to that of the M5, M6 and M6 cabrio, but you won't hear us complaining about a formula that serves up over 500lb ft of torque, a 0-62mph time of 4.2 seconds and a 190mph top speed. Both those numbers pip the M5 by a fraction, which may have something to do with the GC's marginally more slippery shape but certainly nothing to do with weight: in fact, the coupe-style four-door actually weighs a few kilos more than the saloon.
So what's the fatty like?
Fast. Heinously, autobahn-smashingly fast. The M6 GC charges for its delimited top speed with the head-down, blinkered insanity of a bull elephant on an urgent booty call. At any speed, any revs, the GC offers up a wrecking-ball thump of power, firing you off deep into the middle distance and far out of sight of just about anything else on the road.
And now we've finally recovered from the shock of big M-cars going turbocharged, can we take a second to appreciate the sheer excellence of this monster V8? It's a mighty thing, capable of calmly woofling along at low revs before serving up a gut-punch of torque that gives way to a headlong, rousing charge past 7000rpm. This is 21st century muscle, and we love it.
And for those of us who don't conveniently encounter an autobahn on our morning commute?
Still fast. On real, normal-sized roads, the M6 is a touch more wieldy than its dimensions and kerbweight would suggest. Perhaps it's the dropped roofline and carbon fibre roof lowering the centre of gravity, perhaps it's something to do with the gently revised steering and throttle maps. Most likely it's just the psychological effect of its squished glasshouse and wraparound cockpit. Whichever way, the M6 feels a mite more compact than the too-big-for-Britain M5. OK, it won't squeeze down country lanes like, say, a Fiesta ST, but the GC still inspires a touch more B-road confidence than the M5.
Quite a lot more horsepower than the Fiesta ST, though.
Yes, but despite all that power and the manifest lack of a driven front axle, you rarely worry the GC will overwhelm its rear tyres, so metered are its responses and smart its many traction control gubbins. Of course, it'll indulge in vast, raunchy drifts if you so desire, but most of the time the M6 GC makes its power gloriously accessible.
See more pics of the BMW M6 Gran Coupe
Yeah, but so does the M5. And it's £15k cheaper. With space for five full-sized people. So why shouldn't I buy that?
True, Top Gear would usually advise you ignore your inner diva, save the cash and opt for the simpler saloon (actually, we'd usually advise you to opt for the estate, but sadly BMW doesn't offer an M5 Touring yet). But in this instance, we'd have to say the GC is worth its premium over both the M5 saloon and two-door M6.
We worried the gap between those two was so infinitesimally small as to render the M6 GC redundant, but, with its frameless doors, bespoke M-Division goodies - carbon ceramic brakes with gorgeous gold calipers, new twin-strut front grille, neat rear diffuser - it really does feel far more special than either.
To our eyes at least, it looks fantastic, no doubt the best of the current M crop and arguably BMW's best-looking M-car in the best part of a decade. And not only is the GC easier on the eyes than the standard M6, but the four-door coupe bodyshell seems a better match for the broad-chested V8 powerplant than the oddly unengaging two-door.
Expensive and odd the M6 GC may be, but it's a winner: certainly our favourite of BMW's big M cars and one of the finest fast Germans on sale. Good enough to defeat the bruising CLS 63 AMG, not to mention Audi's upcoming RS7? It'll be fun finding out...
Torque: 502lb ft
0-62mph: 4.2 secs
Top speed: 190mph (delimited)
Engine: 4395cc V8 twin-turbo
Transmission: Seven-speed DSG, RWD