Whenever a Mercedes-Benz model gets the AMG treatment, you can expect not only a boost in performance but also a great deal of refinement. The SLK 55 is no exception. Dropping in a 5.5-liter V8 with 415 hp and 376 ft-lbs of torque is just the beginning. The sports exhaust opens flaps in the system, letting the raspy rumble of the naturally aspirated AMG V8 be heard loud and clear. The flaps respond to throttle pressure and the system can also be closed for a more subdued ride. Variable valve adjustment, cylinder deactivation, and start-stop technology provide respectable mileage in a car that has marked performance. The seven-speed transmission pushes the rear wheels through a clutch pack instead of a typical torque converter for quicker, smoother shifting. The SLK55 AMG is a dressy competitor in its class, with enough option packages to serve those in search of lavish luxury and pure thrills.