the last SL63 AMG. When that car was launched back in 2008 I assumed it was just a facelifted SL55 minus a heap of torque and with added ugliness. This opinion was shattered in 2009 when, for reasons I still don't quite understand, I ended up running one for a year. It was a revelation. So much better than the SL55 because it had a decent gearbox, was genuinely fast and interesting on account of that V8 and was obviously adaptable because of that folding hard-top. In my mid-30s, I'd become a Mercedes SL devotee - well, an SL AMG devotee, which I suppose is slightly more acceptable.
The new SL63 is faster, more powerful, physically bigger and up to 30 per cent more efficient. It is also another good reason not to buy a Ferrari California.
Luckily for the AMG team, the new aluminium SL platform is a corker. Far stiffer than the outgoing steel effort and 110kg lighter. More than anything else this is the component that allows the SL63 to push the boundaries of this open GT/sportster genre further than any other car.
That rigid structure houses the M157 5.5-litre bi-turbo V8 already seen in numerous other AMGs. This time it offers 537hp (up from 525hp in the old car) and 590lb ft, which isn't even comparable with the 465lb ft of the outgoing model. It doesn't end there either: the test car is fitted with the optional performance pack which boosts power to 564hp and torque to 663lb ft. The Ferrari California has 372lb ft.
New springs and adaptive dampers are fitted, everything is rebushed, the top mounts are new, most of the components for the rear axle are new and cast from aluminium. AMG has retuned the electro-mechanical steering with a direct ratio and a different weighting for Comfort and Sport modes. Those designations are actually transmission maps for the MCT 7-speed, wet-clutch gearbox (ergo: fast shift, heavy steering) which is mechanically identical to the last model's. It aims to offer the benefits of creep and genuinely slushed-shifts, with a snappy manual mode for those who want to make time.
This car is startlingly fast. Mercedes claims it will reach 124mph from a standing start in 12.6 seconds, which feels a little pessimistic given the alarming force with which it slams you down the road under even the smallest throttle opening. It lacks the sharpness of the old M156 normally aspirated motor, but for the job of lumping about an 1,860kg plutocratic open GT with minimum effort it makes the old engine feel like a little Honda VTEC. The gearbox is superb in its comfort setting, often correctly choosing to lean on that torque figure rather than punctuate proceedings with an uncouth downshift. In Sport mode it is more aggressive, bringing burbly blips on downshifts and hanging onto gears longer. Sport Plus goes further with even more engine braking and munitions-grade bangs and cracks on downshifts. Manual does what it says on the tin: slightly slower than a good dual-clutch transmission, but still faster than Merc's own double-clutch in the SLS.
The chassis is fundamentally more talented than before, the stiff structure means no creaks over drainage covers and pot-holes. It's firmer than the SL500, but still very comfortable and it retains control at very high speed on tricky, technical roads. I didn't really bother with the Sport damper setting. It was firmer and flatter, but the less aggressive setting was an excellent one-stop compromise. Combined with accurate steering and massive propulsive force, you have a feeling of crushing superiority over most fellow road users, all the time with the added bonus of knowing that at the push of a button and a 19sec wait you can cruise any boulevard, exposed to the elements, with your arse being warmed and cooled. It's a compelling package.
A locking differential comes as a part of the Performance Pack - you need it to really enjoy the car because good though the systems are, they have to call time too early. There's a touch more lock on drive now than before, but you don't feel any more push from the front axle and you still have to be reasonably brutal to make it pull big slides. Actually, once the tyres are a bit over-warm, that 660lb ft can bring angles well into third gear. It's all very controllable and immense fun. Owners will need friends on the board of a tyre company if they want to do this regularly.
Buffeting is minimal with the electric wind-deflector lowered, non-existent with it raised. Magic Vision wipers squirt without wetting one's head and, when the roof is down, only do so on the down stroke. Can't quite believe I just wrote that. The Airscarf warms your neck and the vast chair really clinches that hard-earned back-fat. Roof up, it's quieter than an XK Coupe. In short, if you require a bigger spread of skills from your hardtop-sports-GT thing, then you'll need to move to another galaxy far, far away.
Sitting 5mm lower on optional forged wheels and with those gold calipers for the, again optional 390mm/ 360mm carbon ceramic brakes, the SL63 looks way better than the standard SL, but it's still not a car you find yourself actively craving just for the way it looks. That's a real shame, because I think it would be an even more compelling everyday performance machine than the last version. Does the Mercedes website do finance quotations?
MERCEDES SL63 AMG
Engine: 5,461cc V8 twin-turbo
Transmission: 7-speed auto, rear-wheel drive
Power (hp): 537@5,500rpm (564@5,500rpm with AMG Performance Package)
Torque (lb ft): 590@2,000rpm (663@2,250rpm with AMG Performance Package)0-62mph: 4.3 sec (4.2 sec with AMG Performance Package)
Top speed: 155mph (limited)
MPG: 28.5mpg (NEDC combined)