need help with a town car

Bag the front with an S-10 cup kit. You will have to modify it to fit a bit. I used a non bolt in set from suicide doors when we originally did my buddies. The rear i would recommend replacing the bags because are not really designed to cycle like our style air ride does. Also 140-200 psi probably is a bit much for factory stuff. My buddies was bagged on 18's with out a notch in the frame and it layed about 2" off the ground (225/40/18 tire) so if you are doing 13's you shouldnt have to notch to lay out. Keep in mind you will never lay frame rails in the front without z'ing the frame as the engine cradle is about 1 1/2" lower then the side rails themselves. These cars arent that hard to bag so i wouldnt cut corners by using the stock bags. The rear setup can be down with lower over the axle brackets from S.S. and the upper part can be done with a universal front cup bolted through the factory spring perchs (have to get all the factory air shit out of there). But like they said you can use the factory bag if you wanted, I just dont trust doing it that way personally.