The on-demand 4WD system in the 2008 GMC Envoy SLE-1 4WD lets the driver select from three different modes -- rear-wheel drive, 4WD Hi and 4WD Lo. Combined with locking and mechanical center differentials and 17-inch wheels with all-season tires, this means the mid-sized SUV can be taken off-road. Unfortunately, it only has eight inches of ground clearance and no standard skid plates. A locking rear differential is available. The engine in the 2008 Envoy SLE-1 4WD is a 4.2-liter, 285-hp DOHC I6, paired with a 4-speed automatic.

New side curtain airbags for both rows of seats join the dual front airbags for 2008. Other safety equipment includes traction and stability control, 4-wheel disc and ABS brakes, passenger airbag deactivation, a tire monitor, and OnStar. In the lighting category, automatic headlights, foglights, daytime running lights, and halogen lamps are all standard. An auto-dimming rearview mirror costs extra. The SUV only earns three and four stars in frontal impact tests, but five in side impact.

Like its rear-wheel drive sibling, the SLE-1 4WD comes well-equipped with full power features, cruise control, new satellite radio, a CD/MP3 player, intermittent front and rear wipers, front and rear power outlets, voice-activated phone, remote entry, leather steering wheel trim, tilt steering, and a tachometer. The 43 cubic foot cargo area features tie-downs and standard trailer wiring (the 4WD cuts towing capacity to 5700 pounds), with the option to add a net and a cover. A roof rack is also standard. Rear seats split-fold to expand cargo capacity to 80 cubic feet. More luxurious options include heated leather seats, power front seats, and a DVD player. Also available are heated mirrors, a compass, side steps, and a 6-CD changer.