I believe that  the stubaxle was changed somewhere about the end of 85
or beginning of 86. The later stub has different caliper mounts and I
think the bearing spacing and/or inner diameters are different.

In order to change over to these stubs you'd need the later brakes as
well, and the South African (as well as Porsche kits) will fit these
stubs. German T3 brakes suck.