I have a '89 N/A. I also have a 88 vert with a s4 TII engine in it. I wanted to know how hard it would be and what I would need to put in the s4TII engine in my S5 and use the S5 harness. I know I would have to have some kind of fuel controller, but other than that what would I need to make the harness work?

 

Don't try to mix electronics & wiring between series. It's a huge mess.

Read this: http://www.rotaryresurrection.com/2n...o_s5_swap.html