Road Test: Mercedes-Benz SL Series SL 65 AMG 2dr Auto Bi-Turbo

The CLK63 AMG Black Series is one of my all-time favourite cars. It's got a mad motor, hooligan-friendly handling and sounds like a whole grid of DTM racers. It's not the fastest or the best handling car you can buy, but it's definitely one of the most fun.

So I was expecting more of the same from the SL65 AMG Black Series, but I didn't get it. For all its killer, stealth fighter looks it's completely different character car from the CLK. Rather than being a race track refugee, it's more a super-sonically fast road jet.

It starts life as a standard SL65 AMG, and there's not much left of it when the boys in the white coats have finished with it. First they rip out the roof mechanism, then pull off pretty much all the panels before replacing them with Batmobile-esque carbon fibre/plastic items.

Next they throw away the heavy air suspension and active chassis control system, replacing it with a tunable coil and strut suspension. And finally they slap on a pair of 12 per cent bigger turbos to the hulking great six-litre V12. There are loads of other detail bits they do too, but those are the headline changes.

The result of which is a 250kg lighter car with 58 more horsepower - bringing the total to 670 - plus the brakes and suspension to keep it all in check. With a top speed of 200mph and acceleration only an astronaut has experienced before, it all sounds good so far, doesn't it?

And it is in a straight line - bullets travel more slowly than this car. The problems start when you try to get the thing to go through a series of corners. It might have shed a sixth of its bodyweight, but it's still no skinny sprinter. The SLBS still squashes the scales to the tune of 1870kg and weight doesn't like changing direction. So, to make it go where you want it to, AMG has remapped the ESP stability and traction controls.

And this is the issue. For all the time spent tuning it at the Nurburgring, after understeering (with it on) or wildly over-steering (with it off) into a corner, the car's weight and enormous power simply overwhelm the onboard brain. While it wonders what to do, you are left sitting there in your £250,000 car, foot on the floor, wondering where it's all going to end.

You can make it easier for the car by summoning your inner Stig and being super smooth and precise, but arrive at a corner you haven't seen before and your chances of getting around it cleanly are severely limited. It's not as exaggerated at normal road speeds, but it's still there. It only disappears completely on long sweeping bends, like you might find on the autobahns, which is where the car belongs.

Not that any of this is really a problem that needs any more dissection. The total production run of the car is just 350 units and only eight of those are currently destined for the UK. With the SLR finishing its run with the 75-unit Speedster next year, this black ops SL will inherit the fastest production Mercedes tag.

Can't argue with that, but I would if anyone said it was also the most fun. That's one title the CLK Black still holds, and tightly too.