Road Test: Mercedes-Benz SL Class SL 65 2dr Tip Auto Bi-Turbo

Breadth of ability is what it's all about these days. And if we're scoring on that, the Mercedes SL63 AMG should do well. It happily occupies the middle ground between a GT car and a sports car - an all-round roadster, if you will (and that is a compliment). A pleasant mix of civilised and thuggish.

How has it managed it? AMG has slotted the 5.5-litre bi-turbo V8 into the SL, so it has a starting point of 530bhp and 590lb ft, a limited top speed of 155mph and a 0-62mph time of 4.3 seconds. In other words, it's deeply, effortlessly fast. Torque-rich cars have always been an AMG speciality, and this SL is no different.

And, thanks to the AMG adaptable dampers, the ride quality is excellent, too. Even on 20-inch alloys, the SL absorbs bumps well, and you never get the sense you're driving a car minus a roof. It's possible to switch to Sport mode, but we wouldn't bother. There's more than enough body control in the Normal setting, and the Sport simply makes it patter more. So the SL63 is graceful, and also...

...Brutal. For the first time, it's available with an optional AMG Performance Pack. Adding around £8,000 to the standard car's estimated £112,000 tag (UK prices are yet to be confirmed), it delivers an extra 26bhp and 74lb ft, thanks to increased boost pressure (from 1.0 to 1.3 bar) and a tweaked ECU. It also drops the 0-62mph time to 4.2 seconds and increases the top speed to 186mph. And for all that extra oomph, it doesn't make any difference to the 28.5mpg or 231g/km of CO2 of the normal SL63.

The limited-slip diff (which is only standard with the Performance Pack) will let the SL do lurid power slides, but, to be honest, that's not a shock. Anything with 556bhp should be able to do the slidey stuff. What's more surprising is how agile the car feels. Slip it into manual gearbox mode (which adds extra weight to the steering but not any extra feel), and it becomes a rewarding thing to thread through corners. The steering is sharp and, because AMG has replaced the normal SL's variable rack with a fixed-ratio, it's easier to place the 63 accurately. This doesn't feel like a big, front-engined barge - it's lithe and fun.

It's impressive stuff, because the SL is a big car. Even with this generation's 125kg weight-saving, thanks to the new alloy body, it still tips the scales at 1,845kg.

But if your tick list for a car looks like this: coupe, fast, convertible, rapid, comfortable, fun, luxurious, quick (did we mention speedy?), then little else matches this SL63. It really is that good.