There is always debate on what will work with the s4 and s5 turbo swaps. So what parts are different between the s4 and s5 turbo cars? Let keep it simple and only talk about engine components.

wiring harness
ecu
rotors
front cover


add to the list and if you know what makes them different add that aswell

 

omp is diff
turbo manifold s4 is twin scrol s5 is not
s5 has biger waste gate
high and low imp fuel injectors
maf is dif

 

flywheel/counterweight

 

S5 TPS has two thingys instead of one...Compression is higher... and acutally the lines on the turbos are different between S5 & S4...