The C63 AMG doesn't feature the new 5.5-litre twin-turbo V8 being rapidly rolled out across the AMG range. Instead, it gets the good ol' 6.2-litre, naturally aspirated V8. The reason? The turbos meant the new V8 wouldn't fit in the coupe's engine bay. That tells you everything you need to know about how AMG works.
Eco-warriors that we are, we should be sad the C-Coupe misses out on the more efficient turbo engine. We're not, for two reasons. First, the free-breathing old V8 is one of earth's great powerplants, and deserves to live on a while longer. Second, AMG has long been the master of the massive-engine-into-smallish-car formula, and the ratio doesn't come any more imbalanced than this: 6,208 cubic centimetres and 451bhp wedged into something barely longer than a five-door Ford Focus. That isn't a car, that's a cluster bomb.
But god, it's good. The C63 Coupe bellows like a freshly branded John Prescott, spins up its wheels with reckless abandon and underlines everything that's correct about overpowered, rear-drive cars.
Blindingly quick, too. The C63 simply obliterates the 0-62mph dash in 4.4 seconds - point-two faster than the current supercoupe acceleration king, Audi's RS5 - and does so in such a no-nonsense fashion that you wonder why manufacturers ever bother with prissy things like ‘four-wheel drive' or ‘subtlety'. Where the RS5 judders its power back and forth trying to keep you on track, the AMG leaves it all up to you. You know where the engine is, you know where the power's going - if you end up in a drainage trench, it's your own fault.
Which might give the impression that the C63 is a scary brute to drive. It isn't. In fact, treat it gently, and it's as benign as a heavily sedated grizzly, ambling without fuss and with a surprisingly compliant ride. But click the gearshifts into one of the sharper settings - the C63 gets a seven-speed, wet-clutch auto 'box - and unleash your Right Foot of Solid Plutonium, and the AMG becomes a reckless, tail-happy loon, an eminently controllable drift thing.
So we'd take the C63 over the RS5 every day. But what about the M3 coupe? The BMW is undoubtedly a daintier drive, and, even though its gives away 37bhp to the Merc, we suspect it'd be a fraction faster around a racetrack. But the C63 will smear a bigger grin across your face every day. It looks delicious too, with swollen front arches, sinewy bonnet budges and a delicate carbon-fibre lip on the bootlid.
Unimprovable, then? Not quite. AMG is readying a ‘performance pack' bolt-on, which boosts overall power to 480bhp. We can't imagine that'll do anything but improve this wonderful, life-affirming object. All hail AMG, where too much is never enough.
We like: This car, and want one immediately
We don't like: Buying new rear tyres every week
The verdict: Stonking. A rubber-devouring, petrol-punishing masterpiece of excess.
Performance: 0-62mph in 4.4secs, max 155mph, 23.5mpg
Tech: 6208cc, V8, RWD, 451bhp, 443lb ft, 1730kg, 280g/km CO2
Tick this on the options list: Limited-slip differential, £1,625
And avoid this: Brown ash wood trim, £275