the borgwarner (hence bw) diff out of - well I think guys use the skyline one for dattos to get disc brakes and the 'right' stud pattern without having to source anything else, just get one of those and shorten, then weld on appropriate brackets to mount to 1200 leaf springs sort of thing.

They are a strong diff, and are upgradeable. you can get lsd (cone type) centres or mini spool centres cheaply enough too. Guys have run sub 10s in (obviously) much heavier vl commodores with them.