3 inches is the border. Personally, i would not go above 2" without LCAs. lifting without longer lowers changes your caster and can lead to wandering on the road or worse, death wobble. all depends on the truck and the condition of the components. 3" is also the generally accepted max for the front brake lines. Gently tweaking the hard line up front can give a bit more room (if the line doesn't crack), otherwise YJ front lines are longer and bolt right in.