What transmission? 6Txxe? Factory obd2 PCMs are pretty awesome when it comes to transmissions... you can use a 4T60e, 4L60e, 4T80e, 4T65e all behind factory pcms. If you are going to try to use some sort of aftermarket transmission box for stupid features like tapshift or whatever, it is a complete waste of time tap shifting a 3 speed.
It really doesnt matter what PCM you use if you have a tuner work on it, the 00+ files are a bit more powerful on a very small level, but they sometimes require security removal/tuning.
