Hi eyebull,
If you google WaffenGotha and look for the parts list of the FWB300, they have a tuning version of the standard ring for the FWB300S.
You should be able to see it quite clearly as they have pictures of both the standard and the tuning versions of the ring. The stepped ring is the tuning version.
I hope that helps as I can not copy the images and get them to stick in my post.