I am doing the same swap in the same car....Use your stock engine harness on your car. You will need to buy a obd2b-obd1 conversion harness. I ordered mine from here http://www.jhpusa.com/catalog/produc...96469dd3f5dd78
you are using this to convert your obd2 car to obd1. Parts that aren't on your car that you need or came with the swap are a b-series shift linkage, b-series axles with intermediate shaft. You will also need a b16 del sol or 99-00 si rear tranny bracket. If these parts did not come with your swap, you need them. Your harness will work but some of the plugs on your wiring harness will not connect to the plugs on the motor. The easist thing to do is cut your plug off and wire the plug from the harness you have with the swap onto your stock harness. These are some of the things I have seen so far....I am getting ready to swap mine in to as we speak and the only thing I don't know right now is if my ac and power steering will bolt right up or do I have to use those off of the swap. See I kept mine ac and ps still connected to my car and I don't want to unhook them if they will bolt on to the motor. But that is my only problem so far, I will find out when I do the swap here in a couple weeks.