[HO455]

Air ride is not for everyone. You have to really want it to put forth the effort to make it ride well. That being said I would bet those 20's your riding on are not helping the at all ride. What tire brand and size do you have mounted on them? Do you have dropped spindles on the truck?
New cars have thousands of engineering hours into making them ride well with large low profile wheels and tires. Spring rates, control arm lengths, mounting location, bushing sizes and material selection, bearing diameters, range of travel, and not to mention all of the variables in the shocks. That is just the tip of the iceburg. You may get lucky and throw a set of wheels on and have them work to your satisfaction, but I wouldn't be so lucky. So learn all you can. Drop on over to the suspension side and spend a week reading. I also recommend talking with various manufacturers about packages that will deliver the ride quality and the look you want. Take notes. Find someone local and have them take you for a ride. Ride quality is an opinion. Every selection you make is a trade off. Your knowledge is the only way to keep the costs under control.
For the ride you describe, the lower you go, the harder it is to achieve. The same goes for tires, the lower the aspect ratio, the harsher the ride. Our truck suspensions were designed to be cheap to build, relatively safe, and not much else.