I'm located in Southern California, and I meant a wiring harness, not a plug (sorry, wasn't quite awake when I posted that). What I meant to ask is if there are there any sensors that are different in the engine when I switch to OBDI . So what I'm looking at is the outlay for a p72 (I'd rather have the knock sensor and the IAB) the hondata chip, a wiring harness, and of course, money for the tune? Also, when I switch to my stock ECU for smog, should I worry about running lean/rich?