I already converted to s5 engine. If i was to replace the ecu to s5 ecu i would need to change main engine harness. What about harnes that controls ign. coils and c.a.s., thats the harness that goes throught drivers side. Would this harness work with s5 ecu?

 

no, you would need to do a lot of rewiring. s5 electronics suck IMO. it would be better to wire in a RPM switch for your VDI.

 

i dont need to connect the vdi, its in open position all the time. I need to make the s5 afm work, because with s4 ecu the afm isnt making any power. Ive also read tht s5 ecu has a lil bit more agressive map then s4 ecu.