Cobalt replaced Cavalier during 2005, becoming Chevrolet's first new compact design in 10 years. Larger and costlier than Chevy's Korean-built Aveo, Cobalt offers sedans and coupes that share underskin architecture with the Saturn Ion, though coupes don't have Ion's rear access doors. Trim levels are base, LS, and LT for sedans; base, LS, and SS Supercharged for coupes. All share Ion's 4-cyl engines. Base, LS, and LT Cobalts have 145 hp. The SS Supercharged coupe has 205 hp. A 5-speed manual transmission is standard on base and LS models, mandatory on the SS Supercharged. A 4-speed automatic is standard on the LT, optional on base and LS. Base and LS models come with 15-inch wheels; 16s are standard on the LT, optional on the LS. SS Supercharged models have 18s, sport suspension, and 4-wheel disc brakes. Air conditioning, tilt steering wheel, CD player, and 60/40 split folding rear seat are standard. ABS is optional on base models, standard elsewhere. Traction control is standard on LT and SS Supercharged, available on base and LS. Other options include head-protecting curtain side airbags with front side airbags, sunroof, OnStar assistance, and satellite radio.