For me, I used the main chassis, dash, and engine harnesses, as well as several additional sensors so it is code free, from my engine donor (99 Honda CR-V) when converting to OBD-2. I spliced the new main chassis harness into the rear harness next to the driver's seat. I added fuel tank sensors in the back. I removed the wiring for power windows and rear doors. While my Civic has the CR-V engine some controls from the 87 Integra were electrically a match to the CR-V and physically fit my Civic so they were used. on the dash harness from the CR-V I removed the power vent controls, though on CRX those may be of use. I used the CR-V under hood and under Dash harness. I also added cruise control and keyless entry. My car electrically is more or less an 99-00 CR-V, just with 86 Civic/87 Integra controls for the user interfaces and old lights spliced in.
My thread if you want to review is here: http://www.redpepper...showtopic=19234
Also, get the FSM and ETM for the source and target cars. makes tracing wires much easier.