A new engine option and standard OnStar assistance lead changes for Saturn's 2006 compact cars. Ion 2 and uplevel Ion 3 sedans and coupes return, as does a sporty Red Line coupe. The price-leader Ion 1 sedan is dropped. All are 4-dr models; coupes have rear "access" doors that don't open independently of the fronts. Ion's standard powertrain mates a 140-hp 4-cyl with 5-speed-manual or optional 4-speed-automatic transmissions. A 170-hp 4-cyl is newly optional for 3s. The Red Line coupe comes with a supercharged 205-hp 4-cyl and manual transmission. ABS and traction control are included with the 2.4 engine, are optional otherwise. Curtain side airbags are available for all models. Leather upholstery is standard on Red Line, available for 3s. Split folding rear seatbacks are standard. Coupes include a folding front-passenger seat. Ion doors, fenders, nose, and tail are made of rustproof, dent-resistant plastic composites, but the basic design is shared with Chevrolet Cobalts.