Well i have been researching this for my ke30 recently.
Hilux diffs 70's model around 1370mm wide and to fit into a ke30 you need to move the leafs out a little and it bolts up.
Later model diffs i heard are stonger but also longer. 1410mm for 80's model
You can also go r31 diffs, they have discs on rear standard, easy to get lsd's but needs shortening and custom axels. However it does have 4 stud same as rolla.