A diesel-engine model is a midyear addition to the 2007 GL-Class lineup. This premium large SUV is essentially a stretched version of Mercedes-Benz's midsize five-passenger ML-Class wagon. Both have car-type construction, but the GL seats seven, has more towing capacity, and more available off-road equipment. The new GL320 CDI has a 215-hp 3.0-liter turbodiesel V6 engine. It joins the GL450, which has a 335-hp 4.7-liter gasoline V8. Both GLs have a 7-speed automatic transmission with steering-wheel controls for manual operation. All-wheel drive is standard. An optional off-road package adds low-range gearing, locking center and rear differentials, and allows up to 2 inches of additional ground clearance. ABS, traction/antiskid control, hill ascent/descent control, and height-adjustable suspension are standard. So are front side airbags and curtain side airbags that cover all seating rows and include rollover deployment. Options include leather upholstery, navigation system, DVD entertainment, front/rear obstacle detection, and keyless ignition. Also available are steering-linked xenon headlights, and Mercedes' Adaptive Damping suspension that includes driver-selectable firmness settings.