I think everyone is wandering about how to hack up the harness. I can't tell you because I got mine pre hacked
But all you need is Z31 schematic, ZXT schematic, colored pencils, and alot of time stearing at lines. Once the harness is really, only thing you do is pretty much hook the sensors, grounds, and harnesses.
Here is what you need to get Z31 ECU run
12V to MAF from an ignition realy
12V for self cleaning
grounds to MAF
0-5v signals to ECU from MAF
TPS (no mod there)
CAS (no mod there)
12V constant from a battery to ignition relay
ignition 12V from the ignition switch
ignitor
Dizzy CAS swap
6 injector signals from ECU to injectors
I think that's all I got hooked up.