I had to do it when I did my swap. I would recommend buying a harness from HASport. My car runs good but the engine bay looks like crap, and it took me quite a while to do and get right, and I'm an electronics technician by trade. As far as just doing it on a d15, I would say go for it but for the cost of the parts you could probably do a zc or just an Si engine swap.

Rob