The Mercedes-Benz M-Class became more powerful in 2008, thanks to the addition of the new ML550 trim, which replaced the ML500. As its name indicates, the ML550 comes equipped with a 5.5-liter, 382-horsepower V8 engine, the same engine Mercedes dropped into the E550 sedan, the CLK550 coupe, and the S550 sedan, among other vehicles. This powerful V8 drives the midsize ML550 SUV from 0 to 60 in 5.6 seconds, which should enable drivers to complete around-town chores in record time. The ML550 features some design tweaks provided by AMG, Mercedes' in-house tuner. AMG design elements include new front and rear bumpers and five-spoke AMG wheels. Other design elements exclusive to the ML550 include chrome grille ribs, square stainless-steel exhaust tips, and grommeted running boards. The ML550 joins a solid lineup of SUVs that also includes the diesel-powered, fuel-efficient ML320 CDI, the V6 gas-powered ML350, and the top dog in the M-Class, the ML63 AMG, which features a beefy 503-horsepower, 6.4-liter V8 engine and body styling by AMG. All SUVs in the M-Class come equipped with the Mercedes 4Matic all-wheel-drive system, which provides improved handling, stability, and traction in all types of driving conditions. Other features include Downhill Speed Regulation, which manages the throttle and brakes to ensure safe driving on steep slopes, and Hill Assist, which prevents rollback when the driver switches between the brake and gas pedals on steep uphill or downhill grades.