it's not hard, I've done it, you'll need the crossmember and drivers side engine mounts, this si the most difficult part just dow to pita factor, also your car being an 85 you'll need the alternator harness and moutn fomr a turbo or an 87-89 n/a
otherwise you need the injectors, turbo, drivers side manifold, oil lines (and pan) I can't recall for sure but I seem to recall the mas is the same, I went megasquirt, the n/a engine can handle the boost so long as you don't get greedy, intercooling is key
yes the easy answer si to find a turbo z31 but decent ones are getting hard to find