I know your gonna say sell the GXL and buy a TII with the money. Well I bought the GXL for $300 usd not running and made her work. Now she no run. I'm getting a TII with big body rust but seriously good running engine and good powertrain. Its an S4 TII and S5 GXL. I have S5 intake mani for a TII, the AFM, Boost sensor, And everything to make it an S5 TII except the Turbo(coming soon) I was wondering if the S5 TII wiring harness will work with the S4 injector. And will the S5 intake mani bolt right up to the S4 holes. Thanks for your input guys.
Charles

 

The S4 injectors (both the 86-87 and the 88) will use different plugs than the S5 (even though the resistance of the 88 injectors are the same as the S5).

If you are going with the S5 intake and throttle body/accessories then you may have to swap the front cover of your S5 13BT as well so you can use the electric OMP rather than the mechanical one that the S4 uses.

The only other issue that I can think of would be that the timing on the leading plugs for the S4 is a little different than on the S5 motor, so using the S5 computer you may have to play a little with the timing to get it to idle correctly. I haven't done a backwards swap like you are trying, but I would think that might be a concern. Maybe someone else will know for sure.

 

I forgot about the front cover, I got that as well. Thanks icemark your a big help.
Charles