The larger of Chevrolet's two midsize sedans gets no major changes of note for 2007. Impala comes in LS, LT, LTZ, and sporty SS trim. LS and LT 3.5 models have a 211-hp 3.5-liter V6 engine. A 233-hp 3.9-liter V6 is standard on LT 3.9 and LTZ versions. SS models have a 303-hp V8 and sport suspension. New for 2007 on the 3.9 V6 and carried over for the V8 is GM's Active Fuel Management cylinder deactivation. A 4-speed automatic is the sole transmission. ABS and traction control are optional on LS and LT 3.5, standard otherwise. Curtain side airbags are standard on all. Impalas have front bucket seats. Optional on LS and LT is a front bench seat for six-passenger capacity. OnStar assistance is standard. Leather upholstery with heated front seats is standard on LTZ and SS, optional on LT 3.9.