Just saw the huge fisty cuffs.
IMO' R31 diff would be a fine upgrade. I have played with a mate on his R31 and swapped out and stripped axles. The alxes in them were incredibly large, aswell as the spline. Bigger than my F series thats for sure. Also you CAN get Kaaz 2way for them now. Our local guy Jacek has one in his now and original ran a mini spool. the only downsides I see are
-I was told by a reputable person that the borg warners are weak, but just the centre itself. You can replace it with the mini spool or kaaz.
- The brakes are fucking pitta. cables/pistons.. Unless you go throuhg replacing the lot, cables/rebuild/exhange calipers, it doesn't seem worth it. Unless you are in love wiht a hydro handbrake.