"A change in automatic transmission and some freshened styling are Ion's 2005 news. These compacts from General Motors' Saturn division come as sedans and as 4-dr coupes with small, rear-hinged back doors that don't open independently of the front doors. The base engine is a 140-hp 4-cyl. A 5-speed manual transmission is standard, and for '05, the optional automatic is a conventional 4-speed. This replaces the previously available 5-speed automatic and continuously variable automatic (CVT). Coupes also come in sporty Red Line form with manual transmission, a supercharged 205-hp 4-cyl, and 4-wheel antilock disc brakes. Other Ions have rear drum brakes and offer optional ABS bundled with traction control. Optional are head-protecting curtain side airbags that cover both seating rows.

Sedans and coupes come in trim levels labeled 2 and 3; sedans also offer an entry-level 1 series. The 1s have 14-inch wheels, 2s have 15s, 3s have 16s, and Red Lines have 17s, plus a sport suspension and their own exterior and interior trim. All Ions get revised steering and suspension for '05, and 2s and 3s gain new front and rear seats in retrimmed interiors. Leather upholstery is standard on Red Lines and optional on Ion 3s. All come with split folding rear seatbacks. Coupes add a folding front-passenger seat. The 2s and 3s are available with OnStar assistance, and satellite radio is optional for all but 1s. Ion's doors, fenders, nose and tail are made of rustproof, dent-resistant plastic composites. Ion shares its basic design with the Chevrolet Cobalt."