Perhaps the dumbest dpfi-mpfi question ever

[hunterhound]

Here it is, really, really, dumb *** question, brace yourself:
I have a d15z1 (vx engine) complete with almost the entire engine bay harness, the p07 ecu, an obd0 to obd1 conversion harness, and an mpfi fuel injector resistor box, going into 89 dx. The question is, other than wiring the resistor box, what other wiring conversions are needed? If I'm using the proper ecu, then I should not need to repin/splice any wires at that point. And the conversion harness should make the connection to the ecu a piece of cake, right? Enlighten me to why I will need to do all of these wiring changes I have seen on-line because it seems as though they all relate to converting dpfi to mpfi AND using the ecu that came with the dpfi engine/chassis.