The Mercedes-Benz SL63 AMG (www.mbusa.com) represents a more powerful, larger-displacement transformation of the already über-enhanced SL55 roadster. The new car’s numerical moniker denotes (somewhat inaccurately) its 6.2-liter, naturally aspirated, 8-cylinder engine, which replaces the SL55’s supercharged 5.5-liter V-8. Designed entirely by AMG, the new motor develops 518 hp, an 8 hp increase. And although torque drops from 531 to 465 ft lbs, 90 percent of that power is available while the engine is loafing at just 2,000 rpm.
In addition to a superior engine, the $138,475 SL63 has a lower chassis, a tighter suspension, and cleaner exterior lines than the SL55. The 7-speed automatic has dropped the old torque converter in favor of a quicker wet start-up clutch; in manual mode, this transmission shifts gears in a tenth of a second. Perhaps the cleverest new feature, however, is the optional Airscarf, a climate system that blows warm air onto passengers’ necks and allows them to drop the top even when the outside temperature calls for cover.