i have done the jzs171 into the mx83, it wasn't difficult. What are you stuck with? Some simple pointers are...
Power the ECU first, constant power and accessories power to the ECU. The ecu then powers the main relay trigger, which gives the ISCV power long enough so it can return to the home position. The BM Pin also needs constant power, this is to power the throttle body.
The Main relay powers the injectors and coils + iscv + heated 02 sensor.
Before advising anyone to attempt to wire a car themselves, i ask the question what is a continuity test, and how to relays work. How do you negative switch a relay and what is the difference between an ECU input and output?
If you can't answer those, then please save yourself a headache and pay someone to do it.