noob question, which nissan xterras ring and pinion work with an s13 diff?

[driftfreek]

i have read that some xterras and frontiers have a final drive gear ratio of 4.636 which is what i want for my s13. but i am getting confused. is it the front diff, or the rear diff what i need? does the c200 R&P work? what year, 98,01,02,etc? what model, se, xe? does anybody know for sure which to use? i would really appreaciate the help. just to make it clear, i only need the R&P, not the whole pumpkin or case.

thank you