just about the only and the biggest problem my 4.8is has, replaced both front air suspentions, and still have selflevel susp inact error, have to change compressor now, it ALMOST SEEMS LIKE BMW SELLS US THEIR CARS TWICE, FIRST TIME WHEN WE ACTUALLY PAY FOR IT, AND THE SECOND TIME WHEN WE REPLACE ABOUT 50% OF THE CAR LITTLE BY LITTLE