I'm still seriously considering a 2006-2009 A6 wagon. The 3.1L engines appear to be pretty reliable. As I've been looking at ads, I see many at or near 200K miles.
Unfortunately they seem to be holding their value pretty well. Cars with 60K miles are pushing $20K. Feels like a lot. At that price level I start looking at how much Mazda CX-5 or Subaru Outback I can get for the same money. This whole practicality thing stinks.