Searched, still have ? about vibes

I have searched a lot, but I never got a clear answer even though the topic has been covered many times. I have a 99 with 3" lift, want to go to 4.5" with shackles and spacers. I have zero vibes now, should i have any problems with the extra 1.5", I can live with some vibration, I just want to make sure that there wont be any complications. I have a 8.25 in rear and command trac, if it makes a difference. Sorry for asking a ? that has been run in the ground.

As long as you plan on a SYE, tracbar, CAs and other minor tweaking you shouldn't be suprised. I'm not sure what all you have now but my 00 badly needed a SYE with 4.5kit. Rensing

i only have the lowered control arms, i was hoping to be able to get away with out the sye

If your LCA are adjustable you stand a chance with pinion angle. But, without pushing the axle forward with adj.UCA you may run into problems.
There is no way around the SYE. 97+XJ output shaft on the transfer case stick out too far from the rear output bearing. Rensing

SYE or dont lift it. Period.

i guess hack and tap would be the cheapest way to go, what kind of shaft do i need to get with that, and kind of money am i looking at. I am on a college budget, so i guess i could eat every other day and save.