Im buying a Rev up engine to build up with TT and all that, my question is, once Im ready to put the new engine in my 03 non rev, will the harness and ECU still work or do I need to get a harness and ECU from a Rev up car?

 

I think you'll need a harness and ECU. There are two different harnesses for the VQ35DEs, but I'm not sure if the difference is the years and different motors or if it's Z/G...

 

My first thought is this: Do a stand alone for the motor and let the existing ecu control everything else. I think that would be the easiest and best way to do it IMO.