Nuts and Bolts Under the 2006 Mercedes-Benz CLS500’s hood is a gem of an engine, a 302-horsepower, 5.0-liter V8 that produces abundant acceleration. Power is delivered to the rear wheels in true sports sedan fashion through an excellent seven-speed automatic transmission.

Under the 2006 Mercedes-Benz CLS500’s hood is a gem of an engine, the same 302-horsepower, 5.0-liter V8 that propels the E500 sedan with authority. The refined powerplant produces abundant acceleration thanks to 339 lb.-ft. of torque that’s available across a wide powerband from 2,700 to 4,250 rpm. Add relatively low emissions and the auditory satisfaction provided by a nicely tuned exhaust note and it’s all the motor most drivers will ever need.

Power is delivered to the rear wheels in true sports sedan fashion through an excellent seven-speed automatic transmission. In addition to making the most efficient use of the engine’s broad power band, this sophisticated unit offers a Sportronic manual shift feature that allows the driver to run up and down through the gears with a sideways tug of the console-mounted shift lever. Selectable Comfort and Sport modes also make it possible to adapt the transmission’s shift patterns to suit the driver’s tastes.

One downside to this powertrain is that, like most high-end automobiles, it requires a steady diet of pricey premium fuel. Our test car returned 15.5 miles per gallon in a mix of city and highway driving, or just slightly less than the CLS500’s EPA fuel economy estimates of 16 City/22 Highway. With a 21-gallon fuel tank, that gives the CLS500 a range of 325 miles between fill-ups.