www.autohausaz.com
the parts are super cheap, and they are OEM.

www.vwparts.com
The best support I've ever had, prices are sometimes higher, but you will get your package withing 2-3 days everytime.

www.parts4vw.com
The owner owns an Audi and can get parts for you if you ask for them, usually a good deal, and the service is excellent.