how high without vibes

hi i am new to this board. i have been jeeping for 6 years though. i just got a 00 xj limited. i am wondering i have heard the newer xj's suffer frm vibes easierthan the olderstyle. my old 96 didn't vibrate much sitting at a true 4" in the back with a 1" t case drop.that was with a aw4 231 and 8.25 combo my new xj has the aw4 242 combo with a d35. i am considering the re 3.5" super ride with rear leafs but dont want to run into vibes. i just found out i am ging to be a daddy so money is tight. my plan is to go re 3.5" with re trac bar 456 gears with true tracs and 265 75 16 on my factory wheels and some skids. thanks for any input , josh

I lifted my wife's 2000 2" with Teraflex spacers and Chevy lowering shackles. I had to drop the t-case to get rid of some nasty vibes. I'll play around later with some shims on the rear axle (Chryco 8.25") to see if I can dump the t-case drop,but for now it's working just fine.