Okay... honestly those shocks havent gotten great reviews from most of the new genreation frontier/xterra owners.
You have some other options though. Spacer added to the top of your current shock/spring (Calmini, daystar, PRG, top guns customz... etc.). Or you can go with a new spring on your same shock (specifically the AC coils). Or you can go with a whole new coilover combo (Radflo coilovers by PRG).
For more information on how to lift your truck and ideas go here.
http://thenewx.org/phpbb2/viewtopic.php?t=2223