Buick added a new model for 2004: a midsize sport-utility vehicle that shared its basic design with the Chevrolet TrailBlazer, GMC Envoy, Oldsmobile Bravada, and Isuzu Ascender. TrailBlazer and Envoy offered both a 5-passenger regular-length version and 7-seat extended-length model. Rainier came only as a regular-length 5-seater. A six-cylinder engine was standard, with V8 power optional, making Rainier GM's only midsize regular-length SUV to offer a V8. A four-speed automatic was the sole transmission. Rainiers could have rear-wheel drive with traction control, or all-wheel drive that did not include low-range gearing. CXL and CXL Plus trim levels were offered. Both included antilock braking, a load-leveling rear air suspension, and 17-inch alloy wheels. Also standard were leather upholstery, dual-zone climate control, and OnStar assistance. Front side airbags were optional. Curtain side airbags were not offered. Rainier was available with adjustable brake and gas pedals, heated front seats, satellite radio, a navigation system, and DVD entertainment. Competitors included the Acura MDX, Lexus RX, Lincoln Aviator, Volvo XC90, Ford Explorer, Honda Pilot, and Toyota Highlander.