I have just bought my first Audi, a 2006 A8L. I have been having it for a few days now. I am starting to notice a kind of roar with some vibration when I am slowing down to stop at like 15ish mph to 0. It also sounds like my air compressor kicks on and off everytime I come to a complete stop. It doesn't feel like a brake issue because there is no vibration in the wheel or any pulsing in the brake pedal as I am pressing it. just a roar from front end and then a vibration that vibrates coins and other thing in cup holders or other compartments. Since this is my first Audi I have zero clue where to start. The car has 86k miles on it. Any advice or help would be extremely appreciated.