The SL is a coupe-cabriolet with a power-retractable hardtop. The base SL 450 gets a 362-horsepower, twin-turbo 3.0L V6. Next comes the SL 550 with its 449-horsepower, twin-turbo 4.7L V8. For more muscle, the AMG SL 63 and its 577-horsepower, twin-turbo 5.5L V8 should do the trick. Finally, the AMG SL 65 has a 621-horsepower, twin-turbo 6.0LV12. Depending on the version, you’ll get a seven- or nine-speed automatic transmission that relays all that power to the rear wheels.