I have a S4 B6, very nice car.
Steering lacks a bit of feel but the engine is lovely and it has plenty of grip!
Sounds superb with a non res Milltek and gutted pre-cats
If you go for a manual make sure it has had a new clutch and flywheel - £2000 job at Audi
Gearing is also stupidly short on the 6 speed manual, 25 mph per 1000 revs in top