Originally Posted by Brad1998RD
Air springs work great. I would recommend doing each line separate so they remain where you put them. Using a single line without a check valve between them air can travel to the other air spring on turns and cause more lean in the vehicle.
I agree. They idea that you stay level with them connected together is not correct unless you have exactly the same weight on each side. The airbags will each support the identical amount of weight as they are at the same pressure, but that doesn't level anything. You need them separated to do any leveling.
If the springs are really bad, which is likely, you may also need to replace them, but if you add airbags at the same time, the springs can be bit softer. This will give you a bit smoother ride, as you will be on the air bags for some of the weight.