Agreed... all about prior maintenance - as with any car really. If you're thinking about a 100k + mile Audi, go into the appropriate forum section and search for common problems with that type of mileage, then compare the service records to common problems found.

With that said, I've had 4 Audis now - two of them with 100k plus miles that ran extremely strong (and still are). I think both owners have them to 160k + miles.