It all depends on which engine you had in the car before you did the swap. I am swapping a '97 B18C1 into a '95 civic DX and I could not buy a harness that would just plug into my ECU because my stock harness did not have VTEC, knock sensor, IAB or VTEC oil pressure sensor. I have to run wires from the B18C1 engine harness to the ECU.

You can get premodified harnesses I'm sure, but it would be a serious pain in the a$$ to replace the harness from the ECU through the firewall.

Brian Wong (bwsf@hotmail.com) can hook you up with just about any harness you need.

Hope it helps.