I don't think they do a kit for 20" cars - you have to buy all the bits individually.
The online catalogue is here:
https://www.meyle.com/en/service-cen...ine-catalogue/
Just search on engine code AVP and it takes you straight to the S8, then
- Product groups
- Axle Mounting/ Steering/ Wheels
- Wishbone/ Swing Arm Joint
- Steering Links (wishbone, trailing link, diagonal arm)