The Sierra gets a new look this year that includes a new front fascia and revised side moldings. On the inside, the Sierra offers new entertainment options, such as a Bose audio system with rear seat controls, XM Satellite Radio and a rear-passenger DVD entertainment system. The instrument panel and center console have been redesigned, and GMC has added new seats, a more comprehensive driver information center and a dual-zone climate control system. For increased safety, Sierras now feature a standard front-passenger-sensing system that deactivates the airbag for children. On the hardware side, the all-new Quadrasteer four-wheel steering system, which increases low-speed maneuverability and towing stability, is now optional. The standard 6.0-liter V8 gets electronic throttle control, as well as the ability to run exclusively on Compressed Natural Gas (CNG) or a mix of CNG and gasoline.