3 inch kits usually suffer with diff cases as it rotas it forward to drop it down to keep the cv angles right,
i did 2 cases in 4 years on a calmini lift 2nd one i changed the rear mount on the diff and the only thing i saw was a few stress highline cracks appear after a year,
i used to run 33.12.50 and a ARB in it. i think alot was down to me having a jap vitara, US kits tended to fit better
when the kit was first on i put 31s and 32mm spacers on with very very slight rubbering at the front,