Overall rating: 4/5
BMW's M division goes to work on the 6 Series, creating a grand tourer with supercar-chasing credentials. Sharing its powertrain with the M5 saloon the M6's higher price and less rounded ability mean it's actually a less convincing package.
In the metal 5/5
BMW's 6 Series just got handsome, and in M6 form it has undertaken the same sort of chiselled sporting makeover Hollywood A-listers undergo to bulk up for action roles. Wider wheelarches, that centre of gravity reducing carbon roof, additional rear lights and massive alloy wheels (19-inch as standard but everyone will tick the 20-inch option box), deeper bumpers housing larger intakes and vents, along with the M6's signature quad-pipe exhaust system leave no doubts as to its potential.
M badging inside, carbon trim pieces and more sculpted, body hugging sports seats grip you tightly. There's a new three-spoke steering wheel, behind which sit the paddles for the seven-speed automatic transmission. The rear seats remain as hopeless as ever, for very occasional short distances use only. All very nice, but not such a marked step up from the already smart interiors of its lesser siblings.
Driving it 3.5/5
With 560hp delivered via a 'TwinPower' turbocharged 4.4-litre V8 engine driving the rear wheels through a seven-speed twin-clutch automatic transmission the M6 holds a lot of promise. And that's unquestionably backed up by numbers that underline its potency, 100km/h arriving in just 4.2 seconds and the sprint accompanied by a blinking ESP light all the way there. Despite this it doesn't feel unruly; its performance is less explosive than the numbers might have you believe. Blame the relative civility of the powerplant, with maximum torque arrival at just 1,500rpm and hanging around until 5,750rpm. It doesn't get particularly riotous until above that though, chasing the red line giving deep chested performance that's extraordinary - yet somehow clinical - despite the soundtrack.
Connection with the car is limited. The ability to fiddle with the steering settings isn't particularly satisfying - all weight (or not) and no substance. There's little feel, even if the front tyres do grip doggedly and turn in proves quick enough. Leave the stability and traction systems to do their work and electronics spend a great deal of time reining in the M6's power, though this is not particularly intrusive on the road - the M6's performance is offered in a realm way above what's sociable in traffic.
The suspension in Comfort mode does a good job of controlling the M6's bulk while providing a supple ride, the Sport and Sport+ settings reducing roll further and incrementally removing layers of comfort from the chassis mix. That's true of the gearshift and throttle mapping settings too, the most extreme modes thumping gear ratios through with unnecessary ferocity and sharpening up the accelerator's response to a level that's best sampled on track.
Two M buttons now exist for such scenarios, allowing you to have a preferred setting for the road, and another, naughtier one if you're at the track. The M6 proves remarkably adept on a circuit, it a triumph of engineering over basic physics, the way it manages its mass being remarkable. Optional ceramic brake discs provide strong stopping power, and choosing them drops 19.4kg from the un-sprung weight at the same time.
While it's impossible not to be impressed with the M's technical competence, it simply doesn't connect on any other level - it's a bit cold, if a car can be described as such - especially one with 560hp.
What you get for your money 3/5
The 6 Series is a difficult car to position, it having few directly comparable rivals. That's even truer of the BMW M6, its price tag putting it above Porsche's 911 Carrera S, right in with the Maserati MC Stradale and Jaguar's ambitiously priced XKR RS. At the top of the 6 Series range it's unsurprisingly loaded with equipment, the M6 buyer unlikely to be ticking too many option boxes, unless you're after those ceramic brakes (from Spring 2013), or the premium audio offering.
Worth Noting
BMW's M division has been unable to resist the temptation to fiddle with things. The gearstick oddly doesn't offer a conventional P for Park, while S mode is manual rather than a more performance orientated automatic option.
Summary
Such is the 6 Series' competence lower down the model range the BWM M6 struggles to make a convincing case for itself. Neither genuinely cosseting GT nor incisive sports car it feels like a model that's trying to be everything for everybody. The fact the M5 does everything it does with more practicality for significantly less money does it few favours. When the forthcoming Gran Coupé M model arrives early next year the case for this M6 will become increasingly untenable - even if the numbers associated with it are undoubtedly remarkable.