to the best of my knowledge:
buying a front is totally dependable on your luck. some may have been taken off from cars that had serious crashes at the back but the owner decided to write it off. only of the signs of of overused are engine wear, worn belts, dried oil, rust, etc. once an NA car has been coverted, a new ECU is preferred to cope with the additional km output.
as for the wiring harness, i dun really noe much abt that so no comments from me.
glenn