Automatic, Under 20K, in Atlanta GA (North of city), Audi A6, Lexus GS, less than 80K miles
Here’s an Autotrader search with a few options: link to Autotrader
Unfortunately, I’m not seeing any A6s with the 3.0 engine (just the 2.0T) in your area. But there are a few GS350s that may be worth checking out.
If those don’t work for you, maybe save that search on Autotrader so that you get email alerts whenever new matches pop up…