OutToWinPAHC wrote: You can also use a Z32 NA VLSD with a combination of one Q45 and one Z32 axles which requires drilling the input pinion flange to match the DS pattern.
The na z32 is a direct bolt-in aside from swapping the rear cover(iirc just for the s13) and getting your hands on some 5 bolt axles. However, the 90-96 q45 diff requires all that you posted above to work, plus swapping to the z32 tt or 90-96 q45 rear hubs(and I think the spindles as well) since the q and the tt z use thicker axles.