AMG hasn’t waited long since unveiling its SL63 before sating its V12 fanatics with a crunching 630 horsepower, twin-turbo V12 shoehorned into the all-new Mercedes-Benz SL body. AMG boss Ola Källenius insists every top-end car that comes out of his hotshop will always boast a V12 because a small, but loyal, bunch of AMG buyers could never bring themselves to own a humble V8, even with two turbos hanging off it. “The combination of exclusive V12 performance and a refined roadster driving experience was already the defining attribute of this car’s predecessor. We are convinced that, with the new SL 65 AMG, we have developed an incomparably exciting high-performance vehicle for the small, but loyal community of fans", says Källenius. That’s a lot of adjectives, but there’s no denying the new car is fast. The 463kW of power it heaves out hurls Benz’s maddest machine to 100km/h in just four seconds and then on to 200km/h only 7.8 seconds later. Only a couple of seconds later still, it will slam into its 250km/h speed limiter, though AMG will remove that impediment for buyers that pay a little more for the even-faster kit. Thanks largely to Mercedes-Benz’s work on the extremely clever, mostly aluminium chassis, the SL65 AMG clocks in 170kg lighter than its predecessor. Before anyone gets cocky, it still weighs 1950kg, which is significant for a two-seat convertible. The first thing you’ll notice are the enormous 255/35 R19 front tyres and the 285/30 R19 rear boots, plus the lowered body and the meaner grille. Inside the 19-inch wheels sit 390mm front brake discs, with six-piston brake calipers, with a single-piston caliper clamping down on a 360mm rear disc. For the first time, the 6.0-litre V12 mates up to AMG’s version of the seven-speed automatic gearbox from Mercedes. It’s a tougher, faster unit, with a proper, electronically controlled clutchpack sitting at the back end of the strengthened seven-speed unit. Like other AMGs with this gearbox, it will have a Comfort mode, with start-stop engaged, a Sport mode, a Sport-plus mode and a manual mode with paddle-operated gear changes. Its suspension runs a retuned version of the Active Body Control system that was unloved on the SL500 when we tested it last month, though AMG assures us its version will be significantly different and more driver oriented, though it suggests the SL63 V8’s version will be sportier than the SL65’s setup. But the engine will always be the talking point for the SL65, even with its folding hard top roof and its glass roof that changes colour for light and shade, just like it does in the SLK. It’s a monster of a mill, and it offers 13kW more than it did in the old SL65. It still runs 1000Nm of torque, which is more than enough for most people, though not as much as the engine is capable of pumping out. The issue is that the gearbox might not live as long as Benz wants if they give it more torque than that, so it effectively limits it at 1000Nm, much as Audi limited its Q7 V12 TDI to 1000Nm. A thousand Newtons, it seems, is about the limit of production gearbox technology today. Though it will barely matter to anybody with the €236,334 it will cost to buy one of these things in Germany, the SL63 officially uses 11.6 litres/100km on the combined cycle, but expect considerably more fuel to be burnt when the two turbos start spinning hard. One reason for that is that it runs bigger exhaust turbos than the V12 has ever done, and it has new exhaust manifolds, too, with new wastegate ducts. Each cylinder gets double ignition coils, there’s a new ECU and its all-new exhaust is 3.2kg lighter than before.