Despite numerous 2003 upgrades, there's not much different on the outside other than optional multifunction mirrors and new machined aluminum wheels for SLT models. Inside, you'll find tri-zone climate controls, an enhanced driver-information center and a redesigned center console and instrument panel. Satellite steering wheel controls are now optional (standard on Denali models) as are second-row captain's chairs. New entertainment options include a Bose audio system, as well as XM Satellite Radio and a DVD-based entertainment system. For increased safety, there are a standard front-passenger sensing system, three-point belts for all second-row passengers, adjustable pedals and an available StabiliTrak stability control system. GMC also upgraded the braking system for better pedal feel and performance and retuned the Autotrac four-wheel-drive system for better efficiency and less binding at low speeds. Finally, Yukons sold in California are fitted with a new catalytic converter that earns the truck ULEV certification.