The Chevrolet Silverado and GMC Sierra pickups boast significant improvements and more than 40 new features including a passenger-sensing air bag, advanced electrical system, modified instrument panel, redundant steering-wheel controls, and new center console. The trucks have redesigned exteriors and also feature the first industry application of a Bose audio system in a full-size pickup and a new, rear-seat DVD entertainment system. There is also expanded availability of the Quadrasteer four-wheel steering system. A range of Vortec engines is offered and two Duramax diesels with up to 340 horsepower. Estimated list price: $20,000 to $41,375.