 I have owned my 2005 Audi A6 Quattro for almost a year now and have have problem after problem. From a rear-end differential to a 2,000 dollar steering module just to start the car even though there were no problems mechanically. I caution you if you’re thinking about buying a used Audi A6 to keep thinking and move on because this car will nickel and dime you until you can’t afford to fix it anymore.