hell, if you have the si underdash, get an si motor harness too so you have to do no electrical work im going to assume you already have the manifold and injectors and whatnot. just install the new disty on your motor, there should be a plug (if you decide to get a si motor harness) to plug into the resistor box. see, you cant just plug an si engine harness into your car because stuff just doesnt match up with the hf cabin harness. but get an si engine harness to make things really easy. the disty basically pops in, and has an "idiot proof" way of going into your head so you cant install it backwards. should be plug and play with the new harness. they are cheap and easy to find too. so i say do that, good luck