So I have around 700 miles on mine and the brakes have been squealing pretty much form the start, same symptoms last 2-3 miles an hour mainly noticeable is start/stop traffic. Doesn't do it straight away seems to take 3-4 miles into a journey then pretty constant, it has been getting slightly better. Anyway the dealer had it today and inspected the brakes. They told me that the brakes were glazed and need some hard braking once they had done that they were fine, they have no service bulletins about RS3 brakes (!!!) and if it happens again I just need to do some hard braking and that this is a symptom of performance brakes. I mentioned that I would be back if this continued (which I am sure it will) and on the drive home only squeaked once very slightly. I'm going to run it for a while see if things improve and do a bit of hard braking now and again. Fundamentally though it's not acceptable for brakes to squeal in this day and age I have had numerous "performance cars" from Audi, VW and BMW and never had this problem, Audi surely can't design something that needs you to hard brake to resolve for a short period of time. The car is so great though that I can forgive the odd squeal.....