Best car Ive owned. Averaged 16mpg over 7000 miles/6 months. An absolute monster out of the box, but expensive - A full set of front and rear brakes, are £1600 ish retail, tyres are £800-£1000, however it is all very worth it. Phenomenal car, if you haven't driven one, try it, you wont be disappointed. As other have said make sure its got a good warranty.
I would ignore what everyone is saying about other cars faster, who cares!, its an RS4, and these other cars are modded.
I also had a resonated Milltek, what a noise.
Had I of not needed the money I would still own mine now.
Do it, you will love it