Large 19-inch wheels and thinner tire sidewalls make for better traction and handling. There are other subtle changes to the front and rear faces of the car to improve aerodynamics, as well. The CTS-V's winglike rear stop light, for example, is taller than in the standard CTS.
The CTS-V is expected to go on sale in the fall.
Last updated January 09 2008: 2:10 PM ET