Photos: 2008 Mercedes-Benz GL320 CDI

The GL-class is a full-size luxury SUV with three rows of seating. This model comes with a diesel engine.

Although built as a luxury SUV, the GL320 is rugged, with standard all-wheel drive.

The 3-liter turbocharged V-6 diesel engine produces 215 horsepower and 395 ft-lbs of torque, the latter number giving the big SUV plenty of boost. Fuel economy is exceptional with this engine, coming in at well over 20 mpg.

The GL-class is very large, making urban maneuvering uncomfortable.

As part of its off-road gear, the GL320 has an air suspension. With it, you can give the car 3 inches of extra clearance over its standard drive height.

The third- and second-row seats fold down, creating a huge cargo area. Even with just the third-row seats down, there's plenty of room.

We particularly like that you can lower and raise the third-row seats with these buttons, set on the wall in the cargo area.

The third-row seats actually have footwells that make them usable by adults. But getting into them can be difficult.

The switchgear on the dashboard is nice, but we don't like the color scheme. The interface for the navigation and audio systems isn't very good.

The GL320 gets a lot of body roll in corners. The steering is fairly responsive, although tuned for lightness to make turning the big tires easy.

We like the information display between tach and speedo, which can be made to show navigation, audio, or trip information.

At the push of a button you can raise the car's height, put it in off-road mode, or activate the hill descent control.

The resolution could be better on the map screens. Street names appear jaggy and are generally only visible when you are in maximum zoom.

The Today's Plan feature lets you input multiple addresses, then have the navigation system determine the best route between them all.

Satellite radio is available with the Premium II Package.

We are disappointed that the stereo only shows file names and not extended track information.

Our GL320 was optioned with a six-disc changer mounted in the glovebox.

The rear-seat DVD player is very inconveniently mounted under the right rear seat.

Rear-seat screen placement is good, as they are mounted in their own casings so as not to interfere with front seat headrest control.

The picture from the rear-view camera is exceptionally fine.