Hey,

So I was wondering how difficult it would be to swap an S5 13B (NA) into an S4 (also NA). I'm trying to see what I want to do power-wise with my car. I don't want to go through the hassle of swapping over a bunch of T2 parts. I was thinking of swapping in an S5 NA engine, and work on turboing that as it has a higher redline.

 

You'll want the s5 ECU to make things easier. The 8k redline... the wiring is different.... the intake also differs greatly. Finally, the S5 has the electronic OMP which only the S5 ECU can operate. Unless you remove it, but then you won't be able to use the S5 ECU.