Mercedes-Benz wants to play hide and seek with its new SL 65 AMG Black Series, with AstonMartin, Ferrari and Porsche hiding, and this 200mph supercarseeking.

Utterly excessive in every aspect, the AMG Black Series is Mercedes’ hardcore, racetrack-tuned sporting range. There are already Black versions of the CLK 63 AMG and SLK 55 AMG, but this is the Black flagship, and one of the few cars on sale capable of making the standard £154,375 SL 65 AMG look cheap. When they take delivery in January, each Black Series buyer (there will be eight in Britain, and just 350 cars will be built) will have been relieved of £250,000. You could have the normal SL 65 AMG, an Aston Martin V8 Vantage and at least £10,000 in cash for the price of one Black Series SL.

What does a quarter-million buy? Well, the primary purpose of the steroidal bodywork of the Black Series is to drop the corpulent SL 65 AMG’s weight by 250kg. AMG boss Volker Mornhinweg expresses the Black Series philosophy as: “Two seats, closed roof, light weight, more power.”

So, on the face of it, using an SL 65 as a host car presents some problems. It has two seats, but like every other SL for some decades now, it has a convertible roof and, at 2,120kg, can hardly be described as light. Which is why the whole roof mechanism has been discarded and replaced by a fixed top made from carbon fibre. Moreover, the rest of that outlandish bodywork, apart from the doors and rear wings, is also carbon fibre, which, as well as being light and strong, is hellishly expensive.

But this was just the starting point. Whereas normal AMG cars can be described as “road cars that don’t feel out of their depth on the track”, the SL Black Series was designed predominately for the track, but with the proviso that it must also be road-usable. This meant a complete change in suspension philosophy, replacing the SL 65’s standard suspension with a race-bred coil system, and pushing the wheels out beyond the standard bodywork - hence those massive wheelarch extensions.

Then they fitted an even quicker steering rack to make the car feel more responsive, and optimised the braking and electronic stability systems for the more intensive demands of the track.

Finally, attention was turned to the engine. More powerful than any other production Mercedes in history, it eclipses even the 626bhp SLR McLaren. How? By fitting it with larger turbochargers, altering the engine electronics and improving gas flow, both into and out of the engine, power has increased from 612bhp in the standard SL 65 to 670bhp.

This means the SL Black Series can accelerate from 0-62mph in 3.8sec, though this is not a true indicator of performance. With rear-wheel drive and the engine in the front, the car lacks the kind of traction needed to record really impressive low-speed acceleration runs. A more telling measure of its performance, then, is that it will reach 124mph from rest in 11sec flat – less time than it takes the average car to reach 60mph. Rather coyly, AMG has restricted the top speed to a mere 200mph. When asked what speed it would reach if left to its own devices, the engineers said: “Perhaps 220mph.”

But even these numbers fail to do justice to how startlingly rapid the SL 65 Black Series actually feels. Apart from the odd badge and carbon fibre inserts, the cabin is standard SL, while the 6 litre V12 motor is limousine-quiet as you cruise down the motorway. But if you floor the throttle, even at 60-70mph on a straight, dry road, a mighty roar from the engine is accompanied by a period of frankly bewildering thrust – followed immediately by a frantically flashing traction control light as electronics try to stop the rear tyres from vaporising.

Although the brake discs are not of carbon-ceramic composite, as you might expect for this kind of money, they are still massively powerful. And that’s just as well, for on the Laguna Seca raceway in California, where I drove the car, they were almost constantly needed to curb the astonishing speed the SL achieves on even the shortest of straights.

Enter a corner a little too fast and it will start sliding helplessly, so the correct approach is to be cautious as you near each turn, safe in the knowledge that the speed you lose on the way in can be recovered with the smallest toe-twitch on the way out.

For all its dizzying speed, if you view the SL 65 AMG Black Series objectively, there’s no way it’s worth a £95,000 premium over the hardly sluggish SL 65: it is just 0.4sec swifter to 62mph, and the only reason a standard SL 65 won’t do 200mph is that it is electronically programmed not to. A rival such as a Ferrari 599 GTB is lighter, quicker and substantially more exciting, although that probably isn’t the point. AMG expects to confirm by the end of this month that it has sold every one of these limited-edition Black Series SLs.

Despite that price and the tricky market, AMG’s customers have clearly concluded that it’s more than worth the outlay.

Hot Wheels specs

ENGINE 5980cc, 12 cylinders
POWER 670bhp @ 5400rpm
TORQUE 737 lb ft @ 2200rpm
TRANSMISSION Five-speed automatic
FUEL/CO2 19.6mpg (combined cycle) / n/a
ACCELERATION 0-62mph: 3.8sec
TOP SPEED 200mph (electronically limited)
PRICE £250,000 approx
TAX BAND G (£400 a year)
VERDICT Every bit as mad as it looks
RELEASE DATE January 2009

- AMG engineers have ditched the SL’s usual folding roof arrangement in favour of a fixed, lightweight carbon fibre top The 670bhp 6 litre twin-turbo V12 is very thirsty, and you’ll be lucky to better 19mpg

- Wheelarch extensions help to accommodate the larger wheels and tyres and those powerful ventilated disc brakes

- It may cost £250,000 but all eight destined for the UK are sold out. Just 350 will be built in total