I posted this over at audizine, thought I'd try to get a couple more opinions here. General consensus is that car is a good deal, probably runs solid if it's made it as far as it has already, and I should do a PPI as with any used car. Here's the summary:

So I'm in the market for a new (used) Audi after passing my B7 A4 avant on to my wife.
I have been in the market for a B5 S4 given that my budget is 10K or under, but I found this B6 S4 on Craigslist and it got me thinking about getting into a B6:
http://cosprings.craigslist.org/cto/3280279603.html

I initially wrote off the V8 in favor of the bi-turbo V6, but have warmed up to the idea of not having to worry about turbos going bad on me.
This car will only be used as a weekend driver since I bike/bus into work, so I anticipate putting 5-7K miles on it per year for the next few years.

I haven't seen any B6's with near this many miles, so I know there isn't a lot to compare it to, but I'm wondering what you current B6-7 owners think about the mileage. Let's assume the vehicle is up to date on scheduled maintenance and regular oil changes every 7K miles or so. Carfax shows 20K+ miles put on her per year over the first 6 years of ownership, so lots of highway miles.

I am relatively familiar with some of the common issues to the V8 (chain-tensioner, etc.) from browsing the B6 forum for the past few days... Any thoughts on the reliability of something like this, given its relative reliability over the course of 160K miles? I know that the longer you drive a car, the more potential it has to break, but I'm looking for specific thoughts/concerns.

Just found out that the current owner, an Audi enthusiast, replaced the original automatic transmission with a 6-speed a couple years ago.
Red flag, or benefit given the shorter life of the tranny? Are there any problems that can arise from swapping trannies assuming its done right?

Am I better off spending the same amount on a B5 with closer to 100K on her or is this a decent option at my price point to be able to get into a B6?