Yeah, I was wondering about 4-links too. I looked on the Belltech, Hotchkis, DJM, and AirRide sites but they didn't have the info I was looking for. Can you install 4-link without air bags? With simple lowering solutions like lowered leaf springs, does adding 4-link improve performance? Simple stuff like that. Perhaps e-mailing the tech dept. is the easiest way. hmmm...