PCM question cause of transmission issues

[GrandPrixGT00]

i have a 2000 stock GT and im pretty sure my PCM is causing my car to jerk when shifting i put a brand new transmission in and am still having this issue so i just need to know about how much is a stock PCM and where are they located in the car

 

[popeyenate]

why stock if you can get an intense a little cheaper, and they are in the air cleaner box

 

[GrandPrixGT00]

whats a good one and i dont race but who wouldnt want some more hp