I just installed a set of Air Lift bags for my Excursion. I ended up buying them on line through a company based in Michigan. I spent some time on the phone with the company that was selling them. The only difference in the two is the jouce bumper which allows no damage to the bag if the bag goes under the 5 psi minimum. Since I am pretty anal about the truck, and I will be raising and lowering the bags often for trailer on and trailer off I opted to save the money and bought the set without the jouce bumpers.
Good luck. I have towed my loaded car trailer and a loaded dump trailer, but not my travel trailer yet. But I am very happy with them so far.
Pro