Air bags give you the ability to level the truck out better. If truck loads up more just add more air in the bag. I've 5100 set at 0.75" air bag can level out the truck with no problem. Even at 1.75" it should work. I've both add a leaf and air bag in the back cause the weight of camper.
How well is the air bags holding up? Im just concerned the bags wont do well with the cold and salted roads. How do you like the ride unloaded?