Unfortunately, the original steering stops are simply not strong enough. They can be damaged by harmless falls or a strong knock.
If this happens, the top yoke (upper) can be damaged, and the fork tubes and Telelever are vulnerable as well. All this can lead to expensive repairs and a great deal of aggravation.
All the listed original parts are not usually available at bargain discount prices, so the investment in damage prevention is always worthwhile.
Wunderlich have opted for a new approach with the R1200GS, here's how it works: the protector brackets bolt onto the lower fork bridge pinch bolts, the top bumpers contact the Telelever just before the original steering stop would make contact.
This softens the blow and as the rubber bumper compresses, it progressively becomes a solid stop for the forks.
Turning the handlebar fully is significantly more pleasant as the hard original restriction is no longer present.
Sold as a complete set of left and right hand side complete with all fittings.