JDM harnesses aren't good for much, except if y ou want to scavenge plugs off of them. Since JDM cars are RHD, the harness is pretty much backwards, and will not reach any of the points you need it to reach. If you don't want to do any wiring, your best bet would be to find a USDM 99-01 GSR harness and use that. Otherwise, use your existing harness and add wires as needed. You mentioned it's a 97 B18C1, which means it's OBD-IIA. Your car is OBD-IIB. You're going to have to figure out what ECM/ECU you want to run, since the pigtails are different between 96-98 and 99-up.