Well looking long term at LSD but not a r31 cut down due to weight etc but see heaps of r180 and Subaru forester lsd diffs at affordable prices.

My query is could they be adapted to a cradle that bolts to the leaf springs?

This may be a dumb idea but better availability than r31 rear ends.

I wouldn't want irs rear end, happy with leaves just looking for LSD options.

Would possibly weigh same or slightly less than r31 rear too.