I love the air ride front on my truck. It handles fine and rides like a dream. If you guys are chasing the steering on your truck, have the king pins, tie rods, steering box and steering shaft checked. If these are in good working order the air ride front drives awesome.
This isn't just stupid me making this comment, a good friend and professional driver with several million miles experience (now retired) helped me inspect and test drive my truck when I first got it. He stated that he loved the way the truck drove, handled and wished his brand new Freightliner drove half as well.
As to changing the ride height, the major question is WHY? These trucks are engineered to ride with a certain distance from the axle to the frame. The leveling valves maintain this. Changing that height changes not only the driveline angles, introducing wear and vibration, but also the alignment of the chassis possibly leading to tire issues or even handling quirks that could be dangerous.