Warren's understating the differences between GTS-T & GTR rear-ends. Just about everything is different between them. You would think Nissan would have kept as much the same as possible, even the way the carrier mounts in the cradle is totally different. You also have another very similiar rear-end to the GTR, that's the R32 GTS-4. I've just recently been GTR diff shopping and it's a nightmare. Seems the easiest way to spot a GTR diff(from GTS-4) is to look for the LSD
oil sticker. Or if it's not there, try and turn the drive shafts to confirm LSD type.
In my books the only reason to chase a GTR diff is to get the (very impressive) mechanical LSD. All the rest are viscous LSD. The 4.1 ratio can be considered a bonus I suppose.
You can see why most Harrison owners just use the GTS-T rear. GTR rear is just not worth the hassle.
The same goes for people thinking that front R32 GTR calipers are the same as R33 GTS-T calipers, they look similiar, but have numerous differences, one difference can cause some inconvenience when upgrading to bigger rotors. R32 GTR caliper is better for bigger rotors, but the R33 GTS-T caliper looks to be a stiffer unit, so who knows which is the best.