I have bags on all fours. After you get over the cool factor it really is a waste of money IMO. The only reason I need them is for the adjustabilty on the fly. Speed bumps and the like. There are many points of failure in these systems....Unlike coilovers. Something most people dont realize is that the system, even the new ones, are not that accurate and once you change ride hide your alignment is out. Lot's of fiddle factor to get the ride height exact so alignment is back to perfect.
If you want to run bags on the front stock suspension then you must leave the torsion bars for support. Just an FYI.
RMS has a system for A Bodies to run the air ride on the front and back. My guess is Bill would tell you that coilovers handle better.
For the rears you definitley want to run a four link. Air ride has a custom four link you can fab in our just go to RMS for the bolt on kit.
One other thing if you are thinking of an air ride system...make sure you order the bags that fit your ride height. You want the bags to be at their most optimal position when you are cruising down the highway. There are many size options and if you get ones that are too long or too short you wont be happy with the ride.
Hope that helps.