Mike at MJP seems very helpfull and will be able to get any bearings, oil seals or shims if you need em (01277 374201) As far as a guide goes I couldn't do any better than the service manual (don't get put off by all the shim malarky cos if you're only replacing bearings I bet you can use the same shims, just keep left and right side clearly marked and separate). I didn't change bearings cos mine all checked out o.k. and I was just trying to get an S15 diff into my housing. Nissan suggest a tool to bolt the diff firmly in a vice and another tool to hold the input flange. I found these to be very handy because of the torque settings req'd and I'll post a pic of what I used when I'm in the garage next.....
