how hard is it?

ok, so heres the scoop...i'm looking to swap my engine in my 88 crx, for a ZC engine. i've got the ecu for the ZC, but my problem is the wiring harness. do i...A. buy a JDM harness for the ZC and extend the wires to make it compadable with my engine.B. buy a conversion kit for my existing harness.either way, does anyone know of a guide i could look at...i really don't wanna screw this up. wiring diagrams for both my exsisting harness and the ZC harness should work to show me what i have and don't have. so those would be most helpful.thanks for yer help.