Just bought a 2008 A4 2.0L S line. First Audi. One problem, rough idling in gear. Otherwise, very quiet, fast and responsive with lots of options. I think I'm going to enjoy it. When I bought the car the salesman indicated that the rough idling was normal and checking with dealers I got the same answer. From driving the car and seeing the technology put into it, I think the manufacturer would be aware of this and have a fix. The car has a few years behind it and I'm sure you've run across this before. I'll review your threads and see what recommendations you've come up with.