I am getting ready to swap my M6 for a A4. Both vehicles are 04 GTOs. I have just a few small ?s however. Do i need the ECM for the car or just the TCM? Also how long can i go on a stock T/C with my mods? Unfortunately i am almost forced to make the swap do to upcoming surgery on my left ankle. And i dont really have 900 bucks to throw at a new T/C right now. Thanks for your help.