2WD= 4 pot fixed calipers 283MM vented discs up front and 273MM solid at rear with single slider affair.

4x4= 278MM vented discs up front and 273MM vented at rear (Single slider affair all round IIRC).

So the 4x4 rears have the advantage of being vented and the 2WD's front calipers better than the 4x4's.

Martin