In motoring, it goes without saying that certain things are mutually exclusive. You can't, for instance, have a low-slung sports car which works off road; you can't have a high top speed and good economy; and you can't have your dignity if you also have a small Korean hatchback. Also, despite many claims to the contrary, you can't have a car which performs well on the Nürburgring and on the ring road. Or, at least, you couldn't until now...

You may imagine that the car you see in the pictures is some kind of DTM racer for the road, as hard as nails, as focussed as a laser and impossibly uncomfortable should you ever be asked to drive across, say, Keith Richards's face.

It isn't. What you're looking at here is the only car I know which really does achieve the impossible. A car that could quite happily get you, and more luggage than you could imagine, actually to Beijing. But which, I suspect, could quite happily bite chunks out of a Porsche turbo's arse on a twisting and deserted piece of Welsh A road.

It comes from the skunk works deep inside the special projects division Mercedes calls AMG. And it's badged simply, and in newsprint-sized letters, as the Black.

The first Black was a disaster. Merc fitted a hard carbon roof, along with hard carbon suspension to an SLK and was undoubtedly very pleased with the way it could handle a race track. But the engineers were so nervous about the way it might feel in the real world, they wouldn't actually let me try one. "It's not very nice," said a Mercedes spokesman. And, from what I can gather from my colleagues who did have a go - many of whom are now being fed mashed food through a tube up their nose - they were right.

The new Black is different. The starting-point is an AMG CLK, which normally comes with a 474bhp, 6.2-litre V8. However, for the Black, a bit of fiddling with the exhaust and the electronics has taken that up past 500bhp. Never mind Porsche. We're deep in Ferrari territory here.

Inside, the posh seats have been replaced with body-hugging buckets. They're so body-hugging in fact, that I'd challenge even Jon Bon Jovi to get behind the wheel and do his seatbelt up.

Other things? Well the seat motors have gone, along with the satnav, the motor for the steering column adjustment, the back seats, and some of the airbags. In addition, the door panels are now carbon fibre, and the net result of all this is that the Black weighs just a tiny bit more than when the engineers started.