I ran the AirLift system in my old Grand Cherokees. Easy install just shove the bag up inside the coil and run the air hose out to an accessible spot. I had the load controller on my first Grand, then just had the bags on my last one. I don't have it on my 03 Tahoe but I always load the rear compartments of the boat as much as possible so it helps to balance the tongue weight. I have even gone to the point of putting my pop bags on the platform (tied off of course) to help balance out the bow weight. I also try to load soda and other heavy liquids behind the boat axles. If you can keep at least 1" of space between the axle and bump stops it should ride decently. If the space gets less than that you are in for a bumpy ride.
actually the Firestone system here looks like a better deal than the AirLift:
http://www.sdtrucksprings.com/index....oducts_id=4435