I previously owned a 2001.5 Audi S4. I was the third owner. I bought it in 2008 with 81K miles. The first two months I had a new clutch put in, hydraulic hood prop rod replaced (the thing that keeps the hood up), and a new alternator. The alternator and hood prop were done by DFW Audi out of good faith (where I purchased the car) the clutch was on my own. After 110K I had the tensioner arm pulley replaced and upper and lower control arm bushing replace along with a CV axel. The clutch cost $1100 out the door at a local trans shop, the tensioner arm pulley was $400 out the door, and the suspension and CV axle were $700 out the door from a local shop. I drove the car until this past November and had put 148K miles on it. I absolutely loved the Audi. I miss it and still don't feel the soul in my 2011 BMW 135 like I did my Audi. Everything about that car worked wonderfully and my experience with the dealer was great! Audi's are just like any other German car, you always take a risk with maintenance and cost, but they just seem to always leave you with smile...at least my Audi did. About the B6 1.8 A4 though, I have had no experience with or heard much on them. I can tell you that Audi interiors are wonderful and durable. Some of the best on the market IMO. Good luck with it, I hope I shined a little light on the matter for you.