well i bought my 01 rs 2.5 for 8,500 with 77,000 miles on it... also buying a super clean engine might not always be the best there might be a reason why it's so clean, oil leaks or coolant leaks, and stuff like that, which you wouldn't be able to notice unless you see the car ever day for a couple days.... just a word of warning, but it all comes down to if you think the seller is trustworthy, you know what I mean? i guess trust your gut feeling and ask lots of questions, was there a high mileage tune up done on the car?
Rafal