Yep, can run 31s safely, easily. No lift necessary, but most do a 1" BL or 2" lift. Seeing as you're in a YJ check out the BL and boomerage shackles (usually 5/8" of lift).
Poverty/College Budget 2004 TJ BB, 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?)