The 2008 Mercedes-Benz GL-Class offers three models differentiated primarily by engines and features. The GL320 CDI uses a 3.0-liter turbo diesel, the GL450 comes with a 335-hp V8 engine, and the new GL550 uses a 382-hp 5.5-liter V8 found in $100,000 coupes.

All GL-Class offerings come with a seven-speed automatic transmission, the 4MATIC all-wheel-drive system, and the Airmatic air suspension system. It comes with seating for seven and with a third row that powers up or down at the touch of a button.

The GL320 CDI and GL450 models are similarly equipped, although not all options are available on both models. All models have a power driver's seat, heated power mirrors, heated windshield washer nozzles/lines/reservoir, reading lamps, burl walnut trim, and so forth.

Options include Distronic radar-controlled cruise control; a rear-seat entertainment system with two screens; Keyless Go, which allows the car to be started as long as the key is inside the vehicle and locked/unlocked with touching the key; Parktronic, which uses sonar to detect obstacles near the vehicle; a power rear tailgate; harman/kardon Logic 7 surround sound system; and DVD-based navigation.

The GL550 comes with full leather, Parktronic, rear-view camera, premium audio, adaptive bi-xenon headlamps, infrared-reflective glass, heated steering wheel, heated front and middle-row seats, and Adaptive Damping Suspension.

Safety features that come standard include eight airbags, including side airbags for all four outboard first and second-row seating positions as well as side curtain airbags that protect occupants in all three rows. It comes with active front head restraints, LATCH tethers for child safety seats, and three-point safety belts for all seating positions; make sure everyone in the vehicle always wears those seat belts because they're your first line of defense in a crash. Active safety features (to help you avoid a crash) include an Electronic Stability Program, anti-lock brakes with Brake Assist Plus, and four-wheel electronic traction control. Optional safety features include Parktronic and a rear-view camera, each of which can help alert the driver obstacles or people, including children, behind the vehicle. The last time we checked, the GL-Class did not come with child locks on the rear side doors.