I have an A6 with only 40k Miles on it with multiple problems. it is a 2003 so it is out of warranty. I spent $1200 at the Audi service shop with a result of them saying they don't know why it misfires. Now the immobilization control unit (some anti theft deal from Audi) has locked the car up and it will not start. They will not give me the codes unless I have it towed to an Audi dealer. I do not live near a dealer so the cost including towing of getting my own car started by a dealer is approximately $2000. I have owned about 200 cars and this is the biggest nightmare I have ever seen. PLEASE DO YOURSELF A FAVOR AND DON'T BUY AN AUDI!