AE86 JDM T series Diff should do the trick, know a few people who have them in Aus but you won't be able to make them part with em!
You'll need the Jap spec dual circuit booster too though
that's exactly what we want, but there like trying to find a kangaroo in AUS that doesn't bounce.
we have in the back of the corolla, AE86 disc brake setup with axles, but with ke70 centre(was made up) breaks axles, the ke70 splines are just a little weak for rallying.
was looking to spend up to a grand, maybe more for LSD one.
rally car has no brake booster, has a balance bar so no problem there.
if you hear of one lets us know