few differences.

kev has mentioned a few.

Obvious difference is 2wd looms are one peice, 4x4 are 3 peice items.

Minor differences are:

WTS guage sensor in different place.
4x4 loom has an oil pressure wire aswell as lambda and knock sensor
2wd loom has a different place where is connects to the main car loom.
TPS wiring is different