OK I am going to go ahead and do the following lift:
http://www.purenissan.com/2_5_shackle_kit.htm I have researched alot and I think I am aware of all the challenges with the UCA, but I have two questions.

1. Has anyone seen a write up on the install with pics for this specific kit, or any spacer shackle kit its pretty much the same? (I will try to do one if there isn't one out there)

2. I am still under drivetrain warranty, does this void it?

I am a noob and have a 06 S Xterra 4X4, going to buy the BFG All Terrains after I get the lift kit and then do the alignment. I am open to all comments suggestions. All help is appreciated.
thanks!