I have a 2007 CPO A6 which we purchased in Aug of 07 with 6500 miles on it. On the dash I saw a message that it was due for service. Car currently has 9300 miles on it. Do I do the 15k service now, or do I just do a oil change and do the 15k service when I hit 15k miles, which at the current rate will be in over a year

What should I expect to pay?

I had the same situation and called the Audi service dept. They told me that If I leased the car, come in at 15k which is the standard service requirement.. I said that I bought the car, then and they suggested 5k intervals is best.
I brought mine into my independent foreign car service guy who has been servicing my Porsche and also races P cars. He said with the synthetic oil, they recommend 7.5k intervals. I had him change the oil and filter which cost approx. $150 (I think my S6 uses more oil than the A6).
I plan to follow his advice.

and contaminants. Then you can decide the interval for yourself.

Terry is an independent professional oil tribologist has worked with RS4 owners for two years now and has extensive experience with AUDI engines. He does private analysis and interpretation for oil companies, auto manufacturers, commercial fleets, racing teams, and individuals. He is the best at what he does.<ul><li><a href="http://www.dysonanalysis.com">Dyson Analysis</a></li></ul>

I changed oil myself after I bought it. It looked black to me and I wasnt comfortable with the 10k Audi recomends. I figure I will take to dealer every 10k and do it myself in between every 5k. I did use correct oil 502 00.

I am more concerned with resetting the service light and keeping my warranty valid. This is the first new car I ever brought back to dealer for service. If I did the services myself would they void my warranty?? This is my first Audi and am not sure if they will let me do it myself.

a quality filter, keep the receipts. I've never heard of a warranty issue. Now if you cross thread the drain or screw up the filter threads, it's another matter....

If you ever use his service, tell him I sent you.