Ok, I bought a N374 J-spec Turbo II ECU, and I ordered a S5 Turbo II J-spec Motor/w trans. OK. I dont know what kind of harness mine is, exp. (N370,N374) Will my ECU work with my harness? Or do you have to have a N370 Harness with a N370 ECU? How does that work?

 

I have done the same thing as you, except I made up my harness from my NA harness. If you swap comes with the harness complete on it, then your OK. If it you have the US Spec harness, then you need the N370. There is a difference in pin location I'm told and I'm still trying to find info on that. Hope this helps.