[MikeB066]

Skip the '03 3.2 for the '04+ 3.6L VVT because the 3.6L drops more power, runs on regular unleaded, and isn't an orphan like the 3.2. Also, the '04+ models don't have the problematic in-dash analog clock that never seems to sync with the real time until replaced by the '04 instrument cluster. Sure, there have been some rear end issues on all gen CTS's but as long as you make sure the car is under warranty, either factory or extended, then you should be safe.

Since the '03 3.2 engine is an orphan, there is a not much aftermarket development for it. On the other hand, the 3.6L VVT is starting to see some aftermarket support, which should be encouraging to any future owner.