When you say "no problems" what do you mean? Have you ever had the air conditioning serviced? Has an engine light ever come on? Are you saying that you've never had any problems, other than standard maintenance, or are you simply discounting the significance of the problems you've had?
Just curious.
Never had the air conditioning serviced on 4 A6's(my wife has one too). The engine light has come on a few times, but I have always been able to drive fine until getting in for service in a day or so. Any problems we had were very minor, not affecting performance.