I've had these wheels fitted to my car this week at my local Audi dealership.
The part number is 8V0 601 025 AT and they are around the £600 inc. VAT.
Wheel dimensions are 19" by 8" with ET49.
I've gone for Michelin Pilot Super Sport – 235/35 R19 Y (91) - which seem fine at the moment with no rubbing. Can't comment on performance, as I haven't leant on them yet, however the ride is a little harsher.
These wheels are special order from Germany, so you'll need to be very persuasive/patient to get them through Audi in the UK... I would suggest using German eBay if your not prepared to wait 8 weeks...
Here's a pic of them on my car (excuse the dirt):
Hope this helps