IIRC its a 32mm. Have a 34mm on hand just in case my memory is bad.
Remove the 4 bolts on the rear of the hub. If I recall they were 14mm, and there are 4 of them. Once they are removed, I used an air chisel to knock the hub assembly loose from the hub, as it is wedged on there, and there is also some residual corrosion that makes it difficult to break free.
Per my earlier post on this subject, the hardest part of this job is getting the damned Deutsch connector disconnected for the ABS sensor. Once they are dirty, they are really hard to work with.
http://www.thenissanpath.com/viewtopic.php?t=5465
When putting on the new hub assembly, ensure that you've wire brushed the mounting surface, and use the 4 bolts to ensure it goes down evenly on the mounting surface by torquing them down a little bit at a time in a cross-pattern.
Looking back on your posts, you've been thinking about doing this for a while. Where did you end up buying parts? How much?
Let us know how it goes, and if you have any more questions.
t