Here is the problem, the exhaust pipes are 2.5" wide, which is a little big for the 3.2L engine. It would be fine for the 3.6L, as several members on this forum have the upgrade. But putting the CTS-V exhaust system on your car probably isn't a good idea due to the lack of back pressure and all the technical mumbo jumbo.
If you want to upgrade your exhaust system, go with Borla, Corsa, B&B, or Magnaflow. Probably going to cost more, but they are designed to work with the 3.2L.
If you want to upgrade your exhaust system, go with Borla, Corsa, B&B, or Magnaflow. Probably going to cost more, but they are designed to work with the 3.2L.