The Mercedes-Benz GL-Class receives a bump in power for 2008, thanks to the 382-horsepower, 5.5-liter V8 engine dropped into the new GL550. As the top dog in the GL-Class lineup, the GL550 replaces the previous year's GL500, and comes equipped with the same engine that powers other high-end Mercedes vehicles, including the E550 sedan, the CL550 coupe, and the S550 sedan. Like its stablemates, the diesel-powered GL320 CDI and the V8-powered GL450, the full-size GL550 features unibody construction, which results in better handling, a smoother ride, and an overall lighter weight, according to Mercedes-Benz. Still, the GL550 weighs in at a hefty 5,434 pounds, but its powerful 5.5-liter V8 nimbly moves all that weight. Outside, the 2008 GL-Class displays a fluid, aerodynamic, and contemporary exterior appearance, with a hunky front end and a swept-back roofline. Light-sensing headlights, rain-sensing wipers, and a sunroof with a retractable sunshade come standard for all GL-Class vehicles. Additional features for the GL550 include a new front bumper design, chrome roof rails, dual heated power side mirrors, and a power liftgate. Overall, the GL-Class comes with the most extensive list of standard features of any Mercedes SUV, offering an upscale alternative to buyers who consider the M-Class SUV to be too small or under-equipped, and the R-Class crossover SUV to be too sedan- or wagon-like. All three trims in the 2008 GL-Class come standard with 4MATIC all-wheel-drive, four-wheel electronic traction control, an Electronic Stability Program, a seven-speed automatic transmission, antilock brakes, and four-wheel air suspension, which automatically adjusts depending on passenger and cargo weight. 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. Inside, the GL-Class comes well-equipped with such features as a multifunction steering wheel, power-adjustable heated front seats, bird's-eye maple or Burl Walnut wood trim, dual-zone climate control, and window-curtain airbags. The high-end GL550 trim adds heated rear seats, leather upholstery, and a wood-and-leather steering wheel.