Driven Hard: Mercedes SL65 AMG Black Series

You can't actually see the entrance to the near-vertical corner known as the corkscrew at Laguna Seca Raceway. You just turn in at a given spot, get back on the gas and launch yourself off the edge of the cliff. In any car it's a thrill, but in the SL65 AMG Black Series it's like sitting at the front of a rollercoaster. There's a small pause as the front tips in, then, as the rest of the car does, too, the whole thing accelerates faster due to the mass of the car pushing it down the hill.

It's a hilarious experience, but such twistery doesn't show off this special new 200-mph Merc's huge abilities very well. What the SL65 Black Series is best at is going seriously fast in a seriously straight line. Corners, for all its new chassis tuning, are not its strong point.

The third, limited-production product of the AMG Performance studio, the SL65 Black Series is a seriously reworked version of Beverly Hill's favorite bi-turbo V12 convertible. In its quest to give its customers a car to compete with Ferraris and Lamborghinis, the company has resorted to some deep surgery. You might not notice all of the changes at first, as the car's silhouette is broadly similar, but the whole car is covered in new details, which goes some way to explaining the eye-popping $225,000 price tag.

First of all, they gouged out and threw away the entire folding-roof mechanism, replacing it with a carbon/plastic lid. Then they did the same with a big chunk of the bodywork. In total, they lost 551 pounds, more than the weight of three average adults, but it's still not exactly light at 4,123 pounds. With no roof mechanism to house, the roofline is lower, and hence the rear windows are new. As are the nose of the car, with its road-hugging splitter, and the heavily vented wheel arches, with their 5.5-inch-wider flares. A retractable rear spoiler that deploys above 60 mph plus 19-inch front and 20-inch rear wheels that are as wide as they are high finish off the outside.

Underneath the new body shell the alterations get serious. The standard car's air suspension and active body-control system have been junked, in favor of a more conventional coil-spring and strut arrangement, with a range of settings plus three-stage ESP. The axles have a wider track and something called the "elasto-kinematics" have been completely revised to make the steering more precise. More fiddling elsewhere has made the steering 8 percent more direct. The brakes are simply and necessarily enormous.

Dr. Black has also clearly been busy in the engine room. Maybe too busy. By the time he had finished tuning the 670 hp motor — bigger turbos, freer air intakes and less restrictive exhaust — it was too powerful for the five-speed gearbox to handle, so they had to dial back the torque to a mere 738 lb-ft. With no restrictions in place, you could add another 20 percent to that figure. The gearbox has four modes: Comfort, Sport, Manual 1 and Manual 2. Manual 2 is 20 percent faster than Manual 1.

The interior of the car doesn't feel as distinct as you might expect. When you are up in the $225K category, everything has to be very special, and the SL65 Black Series just doesn't look that extraordinary. There is carbon fiber all over the place, including one-piece seats for the U.K., and everything works well enough. But it doesn't really offer anything over the standard car, other than the odd creak and groan from the new roof.

None of which matters the first time you put your foot down on the throttle. With all of the torque ready to rock from 2,000 rpm, the SL Black Series doesn't so much accelerate as explode. Sixty flashes up in 3.8 seconds, 125 in 11 seconds, and then...Well, then, the acceleration is so intense you can't see, as your eyes have been stretched back to where your ears used to be and your ears are hanging off the back of your head. It's quite a party piece, but it all goes wrong when you get to the first corner.

You turn in, feed in the gas and then spend the next moments trying to second-guess the electronics. While they are desperately trying to match grip with power supply, you are constantly having to recorrect to keep it going where you want it to. It makes for some spectacular slidey, sideways entries and exits but isn't a terribly quick way to get around a circuit. It's even worse if you turn it all off. For all the electro wizardry going on, it still weighs more than 4,100 pounds, and you just can't hide that kind of mass in a corner.

It is much the same in the CLK Black Series, but nothing like as pronounced. Plus, the smaller car's excellent V8 has far more character than the relatively soulless V12. Personally, I'd have the CLK over the SL any day, if either were available. But with just 350 units being made and only 8 destined for the U.K., the chances of getting either are pretty minimal.

Don't worry, though. If you want to know what you're missing, just buy a ticket to a big rollercoaster. Make sure you get the front seat, close your eyes and you'll be almost there...

Price: Starting at $225,000
Performance: 0-60 mph in 3.7 secs, 200-mph max speed, N/A mpg
Tech: 5980cc, V12, RWD, 670 hp
Top Gear Rating – 13/20