If you’re talking lower control arms, your only choice is OEM or equivalent.
The arm itself is not important (unless your balljoint is f’d), however you can change the lower trailing arm bushing to Whiteline or SuperPro (maybe others).
As for upper arms, you can change all the bushes to SuperPro. Be careful with your bushing choice as the virtual balljoint system requires some flex in the bushes.
There are currently no adjustable upper arms on the market - BUT - I am having a custom set made for me by a mob in the USA, whose name escapes me at the moment. They will be for camber adjustment.
Should have them in the next few weeks, and I’ll pass the details on to the forum here.
As for the brakes, I run EBC USR and RedStuff:
https://www.shopebcbrakes.com/EBC-USR-Slotted-Rotors-For-2010-Audi-S6-USR1520/p95815
I don’t think that’s the price you want to pay, but there’s your part numbers.