the wiring to add vtec to a non-vtec harness is very simple. there will be 1 wire for vtec oil pressure, vtec soleniod, IAB, and sometimes a knock sensor. obd1 is obd1 the same wires even if its an accord, civic, or integra. thats why any obd1 ecu will start and run any obd1 4cyl honda/acura. the only differences are wire colors and manual or auto.