GMC's full-ton pickup gets a full-size update for 2007. The biggest boost comes in the powertrain, with an amped-up 6.0 L, 353 hp or 312 hp V8 that you can upgrade to 6.6 L and 365 hp. You also get increased storage compartment space, new materials to dampen interior noise, and an optional touch screen DVD navigation system. The GMC Sierra 3500HD comes in 3 trim levels: the WT, SLE, and SLT. In addition these 3 levels yield 20 variations from which to choose. The Sierra 3500HD also comes in three different lengths: Regular Cab, Extended Cab, and Crew Cab. Regular Cab trims have 2 doors and seat 3 while Extended and Crew Cabs have 4 doors and seat 5-6. The SLT stands out as the most luxurious make in the lineup and has an elegant wood and metal interior trim to match. Need to change lanes? The Sierra 3500HD lets you blink three times with one touch, making it much less stressful. Overall, reviewers agree that GMC finally made the necessary upgrades to launch the Sierra 3500HD into the upper echelon of pickups. The smooth ride, capable powertrain, and comfortable interior make it a ride to relish. While the 3500HD could use a few more airbags, you'll get your money's worth before you even need to notice.