The answer is that it is way different from the M Roadster, the car that started the M phenomenon in BMW's current two-seater stable. If the M roadster is a stock road car in character, the Coupe is a full-out BTCC racer, an uncompromising two-seater capable of blasting its way to 62mph in 5.4secs and on to a limited top speed of 155mph.
Identical to the M Roadster at the front, the Coupe is new from the A-pillars back. The closed in back end adds stiffness the roadster can only dream about, and it's this that gives the Coupe its hairy-chested character. Step inside and it feels tight. There's subtle retro-style chrome surrounding the instruments and gearlever, figure-hugging seats and a snugness to the cabin you'll never feel in the roadster. Thankfully, BMW has reduced the diameter of the steering wheel in all Z-cars, but tall drivers will still brush their knees on the rim. And though there is a lift-up tailgate to make the Coupe technically a hatchback, it opens on to the tiniest of boots with just enough space for a couple of suitcases.
Yet BMW claims little of this worthy stuff matters to the 200 buyers who will hand over £40,595 apiece next year. What does matter is what's under your right foot, and power junkies are hardly likely to complain about more than 100bhp per litre in a car that weighs just 1,465kg. Fire up that racehorse of a motor and the M Coupe rocks on its beefed up springs, a prelude to thunderous performance. In common with all M cars, there's no traction control which sounds hairy, but the massive 245-section rear tyres on 17in alloys take care of transmitting all that power to the road - in the dry at least: the Coupe simply squats and goes with a toe-curling snarl from its four exhausts.
It's accompanied by a rock-hard ride and a wonderful bellow from the engine, and with five deliciously-spaced ratios connected to a snick-snick gearshift it's easy to feel at one with such a magnificent drivetrain. The brakes, too, take some beating.
But the coupe inherits the roadster's dull steering which spoils the intimacy of the relationship between car and driver. It lacks feedback and can't do justice to what is truly one of the world's greatest engines. You'll be impressed by the performance, but real involvement needs more communication. Which sums up the Coupe. It won't appeal to everyone on looks alone, and it's not the most fulfilling driver's car, but boy if there's a car that gives you a workout every time you drive it this is it.