An iconic convertible, the SL-Class is a grand touring roadster whose hardtop folds back. There are three twin-turbo engines on offer: a 4.6-litre V8 with 449 horsepower (that's 20 more than in 2015) in the SL550; a 5.5-litre V8 with 577 horsepower in the SL63 AMG; and the super-fit 6.0-litre V12 with 621 thoroughbreds and 737 lb.-ft. of torque in the SL65 AMG. The SL line-up is devoid of all-wheel drive, as the 7-speed automatic transmissions relay power to the rear wheels.