[KiltedBanshees93GT]

First off, we'll need to know more about the car. Is it a stick or auto? How many miles? Any mods? What rear gear? These are all able to affect the feeling/performance of the car. Was your friends car the same year/ body? IIRC the SN95's were a good bit heavier than a fox so stock-stock you might notice a seat of the pants difference from that too.
Some good basic things to start out with would be a full tune up, including all filters (add a k&n if you dont already have one and remove the air silencer) new plugs/wires/cap/rotor, check the timing, a compression check wouldnt be a bad idea either. If the timings stock or near stock, bump it up to 12-14*, but back off a degeree at a time if you get detonation.
As far as manuals, first thing would be a Chiltons or Haynes manual (available at most auto parts stores), but there are more detailed ones out there. I perfer Chiltons, but they are kinda hard to find around here.
As to the wiring probs, I would need more info as to what was done to it before hazarding a guess, and even then, I'm no guru.
Hope this helps,
Jorge