Okay guys, heres the situation. A buddy of mine is selling me his Series 5 upper and lower intake manifolds, computer, metal vacuum cluster that bolts to the block , and wire harness (the part that goes to the injectors and everything on the engine and goes through the firewall on the passenger side (pretty big), but to my understanding, it does not include the part that runs the electronics in the car). Is there anything else I am going to need to make this work? He did mention that I may need to have two computers running, one for the engine and the other for the chassis electronics. I do know my way around the S4 engine bay (I just rebuilt this engine and ported it), but not too knowledgeable with the S5. Any help would be killer!
BTW I have an 87 Base with 86 rebuilt engine, stripped emitions, no ps, ac, or air pump

 

I wouldnt mess around with all the computer and vacuum spider stuff. Just bolt on the upper intake to your lower intake and rig up the VDI. This will give you all that you would get by doing all the other crap. TO do the swap you would need to block off the EGR, hook up the VDI to an RPM activated switch, use the old EGR solenoid to work with the RPM switch and supply air to the VDI. And you have to grind down part of the engine where it hits the upper manifold from the S5. Oh yeah, you should also use your old throttle body, you just have to grind off a nipple that keeps it from seating properly to the S5 intake. That way you can keep the OMP linkage (you may have to bend it a little). Also I think the VDI works off of pressure rather than vacuum, so you would have to rig it up to the pressure that is supplied to the 5th and 6th ports. One more thing, you would need the upper and lower fuel injector rails from a S5.

This sounds complicated, but it would be much easier that swapping a computer and wiring harness to convert your engine to a S5, not to mention your engine is the wrong compression, wrong impedance injectors, does not use an electric OMP, and you would probably need a whole bunch of sensors that are for S5 engines.