You will need the 96+harness as for the wiring you will need to make the car have dual o2 sensors(OBD2) as opposed to OBD1 but if you use the harness you will have all the clips and connectors it will be easier that way. If you did want to use the existing 92-95 cx harness you would have to remove the 92-95 harness off of the engine and put it on the new ls engine. But this is more costly and you will need buy an OBD1 distributor and a few misc things cx is a pain but do-able I am almost done with my hatch b16a1 in a 93cxhb....