And good afternoon to you, stout salesman chappy. Now, I' m after a BMW. I wonder if you have anything RWD, with about 550 horsepower and seating for four? The M5 saloon, you say? Far too tall. Far too conventional. Far too much rear headroom. What's that? The M6 coupe? Couldn't possibly get by with only two doors..."
Call Top Gear cynical, but Top Gear suspects this conversation has not reverberated through many BMW dealerships around the globe. But it's to such strangely specific tastes that BMW is apparenly catering with the M6 GranCoupe, a car that, depending on which way you squint, is either a squished-roof M5 or an M6 coupe with a couple of extra doors bolted on. BMW would prefer you thought of it as neither, instead hailing the M6 GC as its "absolute flagship, the most exclusive way to experience BMW". Tough to argue with that one on price: from £97,525, the M6 GC is over 20 grand dearer than the larger M5, and £4,000 more than the two-door M6. Brave sell.
But you know what? The M6 GC, against logic, makes a compelling case for itself against its all-but-mechanically-identical brethren. It's our favourite of BMW's big M-cars, somehow feeling genuinely special - and let's face it, you really want a 100-grand car to feel special - when the M5 seems a trifle chunky and the M6 overwrought.
So how does the M6 GC make sense of its seemingly senseless brief? It doesn't hurt that, speaking entirely objectively, it's the best-looking M-car in a generation. The standard 6 GC is a fine-looking thing, and the M- divisioneers have wisely chosen not to get too heavy-handed with its sporification, limiting their enhancements to a neat twin-strut front grille, a delicate diffuser between the two banks of rear pipes and a stunning set of gold-calipered carbon-ceramic brakes. The interior is similarly restrained, infusing the stock 6 GC's wraparound cabin with a subtle array of M-ness and some natty red 'n' blue stitching.
Ample fastness helps, too. As you may have guessed, with the same 4.4-litre, 552bhp twin-turbo V8 as the M5 and M6, this thing goes like the proverbial off a shovel. Find an obliging stretch of autobahn, and the M6 GC charges towards its 305kph ( 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. Now we've finally recovered from the shock of BMW's big M-cars doing turbocharged, can we take a moment to salute the excellence of this engine? 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 7,000rpm. This is 21st-century muscle, and we love it.
As, yes, you may well point out, you can have all that power and muscle from the M5 saloon for 20 per cent less cash, with an extra seat, more bootspace and proper headroom for rear passengers. But the saloon is a wheezing slowcoach beside the M6 GC, cracking 0-100kph in 4.3secs when the four-door coupe goes a tenth quicker. Maybe those improved numbers have something to do with the GC's marginally more slippery shape, as it's certainly nothing to do with weight: the coupe-style four-door actually weighs a few kilos more than the saloon.
But here's the thing. Despite being no lighter, the M6 GC does seem a more wieldy, pointy drive than the M5. Maybe it's the carbon-fibre roof and squeezed glasshouse lowering the GC's centre of gravity. Maybe it's the lightly revised steering and throttle maps. Most likely it's simply the psychological effect of a tighter cockpit and lower roofline. Whatever, the M6 GC seems to wrap around you a mite more than the M5, changing direction with a little more eagerness, feeling less of a squeeze down drystone B-roads. A little more coupe, a little less limo. The seven-speed dual-clutch 'box, a touch hesitant when parking or inching though traffic, turns santoku-sharp on track-spec upshifts and downshifts, smashing through the gears with crystal clarity.
The M6 GC's neatest trick is that it somehow manages to make five-hundred-and-something horsepower seem friendly-modest,even. You rarely worry the GC will overwhelm its rear tyres, so metered are its responses and smart its traction-control gubbins. Of course, it'll indulge in vast, raunchy drifts if you so desire, but most of the time the M6 GC renders its power gloriously accessible. And, sure, the two-door M6 manages the same impressive duality, but-and again this is wholly subjective - the GC seems a more resolved proposition, the four-door shell a better match for the big, barrel-chested V8 than the curiously unwieldy two-door coupe.
So it's a well-manicured thumbs-up for the M6 GC. Is it good enough to beat the cheaper, even-more-powerful Mercedes-Benz CLS63, not to mention the upcoming Audi RS7, which wraps the same twin-turbo V8 as the RS6 ( tested on page 130) in a coupe-ish body? It'll be mighty close,we suspect, but first there's one more BMW-branded fly in the M6 GC's ointment. The 640d GC. The 640d GC. The range-topping diesel GranCoupe melds that same swoopy body to BMW's lovely 3.0-litre straight- six and comes up with a price-tag some 30 grand cheaper than the M. Though it can't quite match the M6 GC for fearsome, off-the-bat acceleration, with 313bhp and a bruising 646lb ft of torque, it'll get mighty close: the 0-100kph run takes just over a second more than the M6, with in-gear punch that won't offer an inch to the V8 petrol.
No, the 640d doesn't make such a noise (though the M6 is more muted than you might expect), and no, you don't get the M-division goodies, but you'll be able to get to the end of your road without refuelling. On our test run in the M6 GC,we managed 14mpg: our long-term 640d will do over 40mpg, even if you give it some stick.
That said, if you're in the potential market for a £100,000, mediumly impractical four-door, saving the pennies probably isn't a huge worry. If it's gotta be big and it's gotta be M-Division, the M6 GC is as good as it gets.
