Yes I have used them. They were ok up to a certain point, when I started running in the 10's my car was leaving all crooked, one wheel 2ft off the ground and the other still on the ground. I installed a Trick Chassis ARB, problem solved. The ARB keeps the frame and body from twisting (so to speak) and transfers that energy into planting the rear tires evenly. Air bags are basically a band aid that changes the spring rate by adding and taking out air pressure. This is the way I understand it anyway.