I have a 4" ProComp lift on my CJ7. It rides quite a bit rougher than OEM springs or the 2" lift I had on it earlier. In fact, it's a PITA to drive it very long on the street.

1977 CJ-7, fiberglass body, AMC 360 w/ headers, DUI ignition, Edelbrock intake and Holley 4150 carb, TF999, Dana 300, 4.56 gears lockers, York air comp, 4" susp lift, 2" body lift, BFG 35" M-T tires, Megashifter, AGR pump & box, REP8000 winch.