Strut tower to strut tower the ae82 fx is about 3.5in wider than the ae86.
End to end the ae86 is about 6in longer.
Other than head or tail light extensions, will the ae82 FX engine bay harness fit the ae86?

to be honest the layout will probably be wrong youll have better luck putting an fx16 harness instead. Ive converted over the harness and its far easier than to hack up a rwd harness on fwd. mainly because the fx has electric fans and other small things that the rwd lacks. also the harness will probably not reach certain areas so youll have to extend wires and such.