If anyone is unaware, the original wheel valves on the RS can cause a certain amount of bimetallic corrosion on the wheel alloy, to remedy this there are replacement valves available that have a plastic washer at the base of the valve to stop the corrosion. If you are having your wheels refurbished (or tyres replaced) these are a worthwhile upgrade
These cost around £7 each and can be ordered from any BMW dealer: Part # 91.47.3.610.086
Photos and captions below courtesy of Ade Flint:
Here is a pic to show the difference (old valve on left):-

And a pic of the parts breakdown...
you can clearly see the PTFE washer in the new assembly (upper items) used as the new interface with the wheel compared to the old stainless one:-

These cost around £7 each and can be ordered from any BMW dealer: Part # 91.47.3.610.086
Photos and captions below courtesy of Ade Flint:
Here is a pic to show the difference (old valve on left):-

And a pic of the parts breakdown...
you can clearly see the PTFE washer in the new assembly (upper items) used as the new interface with the wheel compared to the old stainless one:-
