message on dash says "airmatic: do not drive car" I push button and car rises.

I am having the same problem with my s430. I have heard a roaring sound for a couple of months. I took it to two different shops.Both shops seemed to think I was imagining it. One shop replaced the boots in rear and a electrical box which was unrelated. Then I took the car home and continued to hear the noise. I took it back to the same shop and they then said it was coming from the from brakes, which did need changing. Changed the brakes and the thing you turn drum or what ever. Continued to hear noise not the mercedes dealer said it was sway bar and bushing. Now my airomatic light comes on. Mechanic said it was because I was leaking fluid in bushing or some pump by the front tire has something to do with the fluids leaking is why the airomatic light comes on. So it is said that I need to change my bushing and sway bar and that will fix problem for 3500 dollars. Too expensive for me I am going for second opinion.