The Bewitching Hour:- An AMG Evening.

There's a homeless man sitting on the bench the on other side of the road. I'm sitting here, in a frightfully well-to-do part of Westminster, in a Mercedes-Benz C63 AMG coupé. I'm sitting on a startlingly comfortable leather recliner, listening to BBC 6 through the Harmon Kardon augmented hifi, and drinking occasionally from a bottle of Tropicana Orange juice. I feel slightly guilty in admitting that, right now, my life is probably a little more rewarding than his.

It's been a slightly strange evening, actually. As you know, the cars I drive are ridiculously diverse; I'd usually be spending my evening in a car worth about one eightieth the value of this one. But tonight, and tonight only, I get to act out my overprivelaged douchebag fantasies.

The Coupe version of the C63 manages to somehow have a personality quite apart from that of its saloon brethren, despite them being extremely similar. Both are brutishly powerful, both are brutally raw, and both are savagely accelerative. One of them, though, feels like a biblically fast C-Class saloon car on steroids. The other feels like a distillation of everything Mercedes-Benz have ever learnt about how to build a fast car.

First, a disappointment. This particular machine isn't fitted with the four and a bit grand AMG Performance Package Plus, which along with some nifty alliteration offers various splinters of carbon-fibre, red brake calipers, and modified crankshaft, con-rods and pistons bringing the total horsepower yield to a tumultuous 487.

My sparring partner tonight makes do with a mere 457, but being disapponted with this is a bit like scoring a night in the same bed as Scarlett Johanneson and being upset that she didn't go all the way.

There are thousands of reasons that this is far from the perfect car for London, but here it does no worse than the average supercar, and an awful lot of the accepted names on that plateau are no quicker than this whiter-than-white, wheeled embodiment of Blitzkreig.

Using all that power in one go is ill-advised on the streets of London, many of which have surfaces that look like they've recently been cleared of land-mines. Get too rash with the loud pedal and you're liable to have the rear end skipping around merrily from pothole to crevasse, a situation which will rapidly develop into a spin if not caught early. Best to resist the temptation and trickle along with the traffic until you reach more hospitable pavement.

Trickling along in the C63 is actually very rewarding, as with every pulse of the throttle you're treated to the ridiculously low rumble of that V8, sounding grumpy and put out that you're not letting it get its revs on. But however pissed off it may seem, it's always ready to respond to a jab of the throttle, pouncing forward with the least amount of provocation.

I probably embarassed myself and won the disapproval of a whole crowd of people, but I offer no remorse about my pulling away from the traffic lights near Harrods on Brompton Road. I was surrounded by cyclists, scooter-mounted couriers and black cabs, all jostling for position like a hyperactive Grand Prix grid. I had probably five times the power of the next most grunty vehicle anywhere near me, yet still I let slip the dogs of war and accelerated hard; right up to 33 miles per hour. Didn't want to push my luck in the strictly policed 30 limit, but for about two seconds the whole of Knightsbridge reverberated with German thunder and I like to think fell completely silent immediately afterwards.

I got ahead of the traffic, of course, all of which then proceeded to call me a wanker and catch up with me at the next set of lights. 

It's hard to explain. Maybe it's something intrinsic about the difference between a saloon car; one with four doors so the family can come along, and a car with only two doors; just for yourself and somebody really special. I don't know. But in coupé form the C63 feels more indulgent, and obviously more exotic. It also seems somehow to look more restrained; the four-door car can come over as a little bit shouty. It wants people to know that yours is the fastest C-Class in the car park. By contrast, the coupé makes a far more confident statement of what it is. It's obviously fast; every model of the regular C-Class coupé range already has purposeful, athletic looks. But the AMG addenda seem more subtle, more like enhancements than additions.

People compare the C63 with the BMW M3; it's inevitable as they're roughly the same power and size and cost roughly the same size hill of money. And, yes; they're both improbably fast and aggressive two-door coupés. But they have such totally different characters that it's akin to comparing Superman with the Norse God of War. They're so different, in fact, that the only real option open to you, I'm afraid, is to buy both.

The BMW still feels like a precision instrument, a scalpel with which to slice sinuously from apex to apex around the flesh of your favourite circuit; whereas the Mercedes is more like a cleaver with which you hack your way through the same meat, leaving blood, gore and carnage in your wake. In truth both methods of surgery take an equal amount of time, but one is beautiful and the other is brutal. But, and I promise that I'm in no way a psychopath, it turns out that brutality can be rather fun.

So, I had fun driving the car the seventy mile journey to get here, I've had fun driving the car around central London, deafening the cultured-up joy-seekers of Soho, Piccadilly Circus and Theatreland. I've had fun parked off Sloane Square enjoying a quick forty winks, waking only as the occasional Lamborghini Diablo or Ferrari Enzo wails past. I now sit in the drivers seat with my laptop, reflecting on how this has been a strange diversion from usual my life on a Tuesday night.

And I feel for the homeless guy across the road from me. I'm not talking about material possessions or lack thereof; for all I know he might have an RS4 at home and just happens to love al fresco sleeping. But he's trying to sleep, and I have to keep the AMG churning away at its lumpy, uncomfortable idle in order to power the laptop without the occurrence of embarrassing battery depletion.

Furthermore, I feel for him because, in about an hours time, I have every intention of performing a full, Sport Plus, five thousand rev launch control semi-smoking start, probably leaving two rich, steamy black lines on Sloane Square. Maybe such irresponsible, inconsiderate behaviour makes me a bad person, but I only have this car until two in the morning.

It would be rude not to.