What SorsCode said is right on. The addition of rear disk brakes in 94 added 3/4" to each side, 1.5" total. If you were to take a fox rear end and bolt it up to the SN-95, the wheels would sit 3/4" further in the wheel well on each side. Of course, this assumes that you had the same backspacing for both the 4-lug and 5-lug wheels.
But if you were to take that fox rear end, and replace the axles and brake assemblies with the SN-95 stuff, it would be identical to the 94+.
BTW, a fox rear end will bolt right up to the 94+ car but I don't *think* the SN-95 brake lines will mate to the Fox axle brake lines (the single rubber line coming from the chassis to the axle housing). It might, but I'm really not too sure.