Chevrolet's popular Impala sedan with a mid-size structure but full-size cabin stocking seats for all in the family, ranks among the best-selling passenger cars in America and it's also the bestseller at Chevrolet. In Chevrolet's 2003 line, Impala scores special 16-inch wheels and new exterior color choices, such as Cappuccino Frost Metallic and Superior Blue. Two trims define the 2003 Impala -- a base model and upscale LS -- and there are two V6 powertrains available. The base Impala uses a familiar 3.4-liter plant from GM that produces 180 hp. An optional 3.8-liter V6 reaches to 200 hp.