I may be able to help you here. your Air bag it kit.. is i personally feel the biggest problem you have. I've been doing air ride for the better part of 15 years. ( i know that means nothing on the web lol) but I've never had a quality product from AIM aka airbagit.com your probably going to be much happier with a kit consisting of quality built parts. i only sell and install parts from major name companies.
Sell your AIM kit and put that money towards better parts and you should be able to install the air ride and never touch it for years.
My Malibu has been bagged for 10 years. I've only replaced the compressors. and i just did that. If you have any questions feel free to PM me and ill give you my number i can answer any questions you have over the phone and well get your caddy down where it belongs.