I thought that VW would instantly dismiss any warranty claim, engine related if any 3rd party oil's are used in the engine?
Hence why Liqui Moly will gladly supply you with the official VW, BMW, Porsche etc etc etc etc approvals which you can give to your dealer when you ask them to do an oil change at a service. That way VW are happy to use a 3rd Party oil due to the TUV approvals and approvals from VW.
Just show the approvals and give them the oil you want to use. VW will gladly use the oil and allow you to keep the warranty.
For your own piece of mind. Ask your dealer but afaik this is the general process in Germany where Liqui Moly is produced.
Besides that VW dont produce their own products. Much like the Liqui Moly approvals VW test oils and approve them. Commonly VW will use Quartz 9000 in the GTI as it is cheap and easy to get hold of.
Mike