i have used the new style air shocks from Pep Boys made by Gabriel, and they ride a hell of a lot better then the old design air ahocks thet were all bouncy and uncontrolled. The newer design is a little stiffer and doesnt make the back end hop over uneven road surfaces.
Personally, I think air shocks are a no-no for any performance app. Get the springs reset or get a new set. If the car is still lopsided with a new set in there then there's some pretty serious body twist somewhere.
I don't think you have a choice now with air shocks, I believe Gabriel's the only choice out there now. I don't know why they get a bad rap now, they were the hot ticket for tire clearance "back in the day". I used em and never had any ride or handling problems. Long as you don't "jack" them all the way up they're perfect for someone to level the body. Back in the 70's and 80's we had no other option, there were no new leaf spring choices, if there wasn't a spring shop around. To level the body side to side, you'll need to route the air lines separately, instead of to a "T".