Unique to the GL550 is a deeper, more aggressive front-end treatment, including a larger three-pointed star that does not accommodate Distronic cruise control. It also features larger fender flares to cover the massive tires and dual-split exhaust outlets.

Seen in profile, the nicely raked windshield and bulging wheel arches over large wheels (18-inch and larger) help balance what is basically a tall and long vehicle. But even being tall and long, the GL doesn't look as bulky as, say, the Chevy Tahoe and GMC Yukon. And even with the squared-off rear edge of its D-pillar, the GL doesn't look as boxy as the Jeep Commander.

Viewed from the rear, the GL offers a formidable stance. It's tall and wide, with a large rear hatch opening and large tail lights, all sitting above a substantial skid plate bracketed on either side by large, rectangular exhaust pipes.

Compared to the ML, the GL is nearly a foot longer overall and an inch wider in track (the axle width including wheels), though it is less than half an inch wider overall and not quite an inch taller. Despite their similar styling, the Mercedes SUVs share only their front doors; otherwise, each has unique sheet metal.

As large as the GL may appear, it's two inches shorter than the R-Class touring wagon, which also has three rows of seating, though with room for only six occupants.

The GL is built using unibody construction rather than the body-on-frame design that full-size pickups and SUVs traditionally use. Mercedes notes that because of this architecture, the GL-Class is 300-600 pounds lighter than its full-size competitors. To make sure the GL class is strong enough, 60 percent of the vehicle structure is made from special high-strength steel.