[WKB]

The R32 uses a viscous LSD and has a ratio of 4.3. If you use a rear end out of a R32 GTR it uses a clutch pack LSD and has a ratio of 4.11. A nissan silva(S14 and S15) differential will also fit and it uses a viscous LSD and has a ratio of 3.77. They are all 200mm.
You could have one each for track or touring as R32 and Silva differentials are pretty common, relativly cheap and it dos'nt take to long to swap.

Warren