I believe it is possible to install Warn #29091 on the Xterra, but I don't think you can install Xterra auto hubs on the R50. If I recall (though it's been a very long time and I could be mistaken), the snap ring fits on a different location on the outer CV axle and it doesn't match the same place on the R50. It would be an interesting experiment to see if it's possible, though.