Somewhere in 1998 or so (?) Ford changed the calipers they used on the SVTs to the size you have now. It is not a defect, and as a matter of fact the swept area is only slightly different between the two. The "big" ones are not as wide, but taller. The "small" ones are shorter but wider (if that makes sense).
For a while, it was a crapshoot to see which car got what based on material supply (I suppose), but eventually everyone got the "smaller" front pad and caliper set.
