You need to first open it up and see if its a CLSD or a VLSD. The r32 GT-R (very early ones) had a CLSD, with the 6 bolt circle input stubs, and they have a larger 31 spline count (if I remember correctly), so your Z axles will not plug into that diff.
If its a VLSD, I don't know what the spline count is, so you may or (most likely) may not be able to use the Z axles...