When looking for air bags on the rear of our units that have them, they are not an OEM item. They were put on by AS. If you mention that you are placing them on a P30 chassis, you will confuse the parts people even more. The front air bags that go in the springs, not a problem.
I like my system with the air compressor and tank set up for the rear. When the weight of the coach on the rear can change over 500 lbs or more during use, it always stays nice and level. Its nice to have the air supply with in a time of need. I have a quick connect hose set up so I can air any of the tires, or air bags on the front if needed.
Chris & Brenda, Members of the Christian Motorcyclists Association
AIR Member 12654
1991 350LE "Zephyr"
1982 310 MoHo
Many Years ago, 1972 Argosy 24' trailer
Our Toad, 96 Saturn SW2 (269,000 and still going