I run air bags and love them but dont go with the firestone kit. it uses one valve stem and a T to fill both bags so when you go around corners and there is more weight applied to one side of the truck than the other the air transfers from the side thats under pressure to the side with less pressure and actually makes for worse body roll than without bags. I use an airlift kit which has 2 seperate air inlets and seperate lines so there is NO air transfer between bags and no body roll. buy the 10k bags as well. mine were less than $300 and I can level my truck right out even with a cabover camper and extremely heavy bumper pull trailer. took me an hour to install.

 

My firestone kit has two lines and schrader valves.

 

My kit for my Chevy alsp came with two lines and two valves. Fixin to get a set for my Ram.