The 2007 Impala comes in four trim levels: LS, LT, LTZ, and SS. The LS and LT have a 3.5L flex-fuel-capable V6, the LTZ comes with a larger 3.9L V6 (now with Active Fuel Management), and the SS has a 303-horsepower 5.3L V8. The V6 engines have variable valve timing, while the V8 is mated to a heavy-duty Hydra-Matic four-speed automatic transmission plus performance-tuned four-wheel independent suspension. Beyond that, most of the differences between trims are in small tweaks, such as fog lights, aluminum wheels (both standard with the 3.9L and 5.3L engines) or heated mirrors (standard on the LTZ).
As with most mid-size sedans, air bags, power windows, power locks, and air conditioning are standard across the line. In addition, Chevy includes one year of OnStar's Safe and Sound plan. ABS with traction control (optional on lower trim levels and standard on the more expensive styles) and standard tire pressure monitor system round out the safety features.