if you have a look at this picture youwill notice 2 arrows

the red one and the yellow one

these are for the normal 2wd cars (even though it's not a cossie you get the point)

the red arrow indicates the width of the carrier where the disc sits in and teh caliper bolts on to
this gap will be 12mm or so on the 2wd cars and 22mm or so on the 4wd cars

the yellow arrow indicates the width of the caliper and the total retracted piston width includes the thickness of the pads as well as the disc
on the 2wd cars this will be the thickness of the disc (10mm) plus the thickness of the pads (another 10mm each) so it will be approx 30mm give or take
if it were the 4wd variant this would be wider by another 10mm at least to account for the extra width of the disc

i hope this clears up any confusion left at the end of this matter

unless someone needs to see a 4wd caliper next to a 2wd caliper?