Chevrolet unveiled the new 2004 Aveo, the manufacturer's new product in the entry-vehicle segment; and the return of the Impala SS at the Chicago Auto Show. The Aveo lineup will include a pair of subcompact models -- a four-door and five-door. The Aveo features a 1.6-liter dual overhead cam 16-valve inline four-cylinder that delivers 105 hp and 107 lb.-ft. of torque. A large intake resonator and dual-muffler exhaust systems help reduce engine noise, and roller-type hydraulic lifters and a rubber timing belt help reduce the need for routine maintenance. The Aveo five-door features a rear-seat that folds and flips forward, creating a cargo area; and the four-door features a 60/40 split folding backseat for easier transport of bulky items. The automaker says the vehicle will arrive in showrooms by early 2004.The Impala SS will return to the Chevrolet lineup as a 2004 model, the company announced at the Auto Show. The vehicle will feature the 3800 Series II supercharged V-6, a 3.8-liter engine that generates 240 hp at 5200 rpm and 280 lb.-fot. of torque at 3600 rpm. The Impala also boasts a comprehensive safety package, room for five, and cargo space. The 2004 Impala SS will be built at the Oshawa No. I Car Assembly Plant in Ontario.