x2 on the airbags. They are adjustable, reduce sag, and can contribute to a more stable ride. When you are empty, air them down to the minimum psi and you won't know they are there. Air shocks are not the same thing and typically cannot handle the loads that air bags can take. Firestone Riderites have the capacity you need and a good rep. I use Airlift but I'm not lifting nearly as much weight as you are.