When the front ends up higher than the rear. Google is your friend. And I guarantee the google machine has a picture of 33s with a 2" lift. Buncha guys run it.
Poverty/College Budget 2004 TJ 2.5" RC coils, 1.25" BL, MML, JK shocks, 33x12.5 Federal MT's
If it can't be fixed with squats or fish oil...your probably gonna die (u aware?)