Yes, the OE units from Audi are fine to use , 1 year warranty on them.
The Arnott Bilsteins being discontinued is good thing !! They were problematic from the get go.
There are many on-line places that offer wholesale pricing, like Carson Heter is a great parts-friend to the Audi community, Milburn Audi is good too, www.parts.com
also has good prices.