I have a 2.5" skyjacker lift. I recently installed a 1" spacer in the front to level it out. I didn't experience any more vibes when I put it in. I am also running 33x12.50's. Since this pic I've added a 1" spacer in the rear also because I didn't care for the level look, but you should be ok. The first pic is with the 1" up front, and the second pic is with the 1" all around.
It's a Jeep thing... You wouldn't understand!
Christian Jeep Club Member #47