I have a '02 xterra was just wondering if put a suspension lift on it would that void my warranty on the x. Called my dealership but the guy that works there had no clue.

That depends on what breaks.

If you install a lift, and the stereo quits, it would be covered.

If you install a lift, and a front axle breaks, probably not.

The way I understand it, and what seems right to me, that is if something breaks on your X and it's proven that your new lift, (or some other non-factory thing you put on) causes the part to fail, then it's not covered under warranty. I.E. If my power windows stop working, it can't be voided because of my non-OEM size tires.