Mercedes replaces the entry-level (or second-from-top, depending on your perspective) AMG-modified roadster, the SL 55, with a more powerful, larger-displacement SL 63. That '63' denotes the AMG-designed 6.3 liter V8 now under the hood. This motor, the first designed in-house by AMG, puts out 525 horsepower, a 10 horsepower bump from the outgoing SL 55. Torque, however, is down to 465 lb-ft. from 531. The new, naturally aspirated V8 replaces a supercharged 5.5-liter V8.

The 6.3 liter, 32-vale V8 revs up to 7,000 RPM, though AMG claims that 90 percent of peak torque can be found at just 2,000 RPM.

The SL 63 is the first Mercedes vehicle to get the all-new, AMG-developed Speedshift MCT (Multi-Clutch Transmission) seven-speed automatic transmission. It features four different shift programs: Comfort, Sport, Sport Plus and Manual. Unlike previous automatic transmissions, the Speedshift MCT replaces the traditional torque converter with a much faster wet start-up clutch. In Manual mode, shift times are cut to 100 milliseconds, a 50 percent decrease over Comfort mode.

A lowered ride height and stiffened suspension again set the SL 63 apart from its more mundane siblings. An optional AMG Performance Package adds ceramic front brake discs, wider rear tires, a flat-bottomed steering wheel with paddle shifters and an AMG-modified Active Body Control system.

Compared to non-AMG SLs, the SL 63 really gets the performance styling treatment. An ultra-aggressive front diffuser with multiple vents, a unique bodykit and 19 inch wheels are standard. The SL 63's bodykit differs from the optional kit for regular SL roadsters. The metal-folding top returns and a glass top will again be an option.