You would be inclined to believe that Mercedes-Benz had the top end of the market covered with its new 2013 SL63 AMG that’s motivated by a twin-turbocharged 5.5-liter V8 producing 530hp (537PS) in standard form and 556hp (564PS) with the optional AMG Performance Package.

Well, that’s not the case as there’s always a number of buyers who don’t mind paying something extra to get more of everything and here’s where the flagship SL65 AMG fits in.

Under the bonnet, there’s an updated version of Mercedes-Benz’s 6.0-liter bi-turbo V12 engine sporting new turbochargers, manifolds and an exhaust system that’s 3.2kg (7 pounds) lighter.

The twelve-cylinder engine’s output is up by 18hp to 621hp (630PS) available from 4,800 to 5,400 rpm while peak torque stands at 1,000Nm (737 lb-ft) between 2,300 and 4,300 rpm.

An AMG SPEEDSHIFT PLUS 7G‑TRONIC with four different driving modes including Controlled Efficiency (C), Sport (S), Sport plus (S+) and Manual (M), transfers power to the rear wheels.

As with the rest of the SL range, the use of an all-aluminium bodyshell results in a significant reduction in weight with the new SL65 AMG being some 170kg (375 pounds) lighter than before. Of course, with a curb weight of 1,950kg (4,300 pounds) the SL65 AMG is no featherweight either.

Mercedes quotes a 0 to 100 km/h acceleration time of 4.0 seconds with the 200 km/h mark attained after just 11.8 seconds. The roadster model’s top speed is electronically limited at 250 km/h.

Not that any typical buyer of an SL65 AMG will care about the car’s fuel consumption, but nevertheless, according to Mercedes, it returns a combined economy of 11.6lt/100, equal to 20.3mpg US or 24.4mpg UK.

The new SL 65 AMG also gets Merc’s ABC active suspension system, beefier brakes with six-piston fixed calipers up front and single-piston sliding callipers at the rear, a 3-stage ESP, and 19-inch wheels wrapped in tires size 255/35 at the front axle and 285/30 at the rear.

The market launch of the new SL 65 AMG will take place in September 2012 with pricing in Germany (including 19% tax) starting from €236,334 (US$308,580). Mercedes has not yet announced U.S. pricing.

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