Set for U.S. sale from November, the up-market performance coupe receives a series of mid-life styling tweaks, including larger headlamps, a restyled grille, more heavily contoured hood and re-profiled bumpers--all aimed at providing the CL63 AMG with added appeal against stiff competition from the likes of the Bentley Continental GT and the newly refreshed Aston Martin DB9.

But it's under the hood where the most significant changes are concentrated. In place of the outgoing CL63 AMG's naturally aspirated 6.2-liter V8, the new model sports a more powerful twin-turbocharged 5.5-liter V8--as previewed at the Geneva motor show earlier this year.

With 536 hp at 5,500 rpm and 590 lb-ft at 2,000 rpm in its standard state of tune, the new AMG is considerably more powerful than its larger capacity predecessor.

As part of a new marketing strategy instigated by Mercedes-Benz, buyers will also be able to specify a performance package that lifts the CL63 AMG's output to an even more potent 563 hp and 664 lb-ft.

Channeling the new engine's prodigious reserves to the rear wheels is AMG's seven-speed multi-clutch transmission. Based on the seven-speed automatic used in the CL63 AMG, it replaces the torque converter with an automatically-operated clutch for more rapid shifts in both automatic and manual modes.

Mercedes-Benz claims the new 4,542-pound CL63 AMG hits 60 mph in 4.4 seconds and has a top speed of 155 mph--or can improve to 4.3 seconds and 186 mph, respectively, when running the optional performance package. With new fuel-saving features such as automatic stop/start and an improved brake energy regeneration system that serves to automatically decouple the alternator under acceleration, it's also claimed to improve fuel economy considerably.

Meanwhile, the revised version of the CL65 AMG also is coming. It receives much of the same visual changes but retains its existing twin-turbocharged 6.0-liter V12 engine with 621 hp and 738 lb-ft-- sufficient to endow the big 4,784-lb coupe with the same 0-60 mph time of 4.4 seconds and a 155-mph top speed as the new CL63 AMG.