I'm tryin' to help my brother out. He has a 96 hx automtic, I'm putting a 94 si 5 speed tranny in it I was just wonderin what would be the best ecu to run in it????

 

The ECU will work but it will throw a check engine light due to the auto trans has a sensor on it. The Ecu will be looking fot that missing sensor, and will complain when it sees it does have one. A good ECU guy can convert your ecu to a 5 spd, i beleive you can get the check engine light disabled through chipping the ECU and a program called crome.