You can do it anyway you want mate.
I have a 3door it's a 4x4 (using full 4x4 late saff engine).
It has a escort cosworth engine loom with an l6 ecu. (the one in 2 parts)
It was running with a 2wd loom and l6 . I stripped back the tape on the loom and extended and redirected certain wires.