Emulators, gold valves, T-valves, intiminators, or whatever you want to call them all work/fit in broadly the same way in damping rod forks. These Ricor ones are very popular on the KLR650 in the states. KLR forks are pretty much the same as those on the XT and there is plenty of information on US forums about fitting. Here's one video, although ignore the music and jump straight to 4:00ish:



I fitted V4S valves by Teknik in Australia, which are similar to Ricor, Racetech et al. They are easy to fit and just involve splitting the forks, drilling out the existing damping holes (so they don't work anymore) and placing the valves on the top of the damping rod/tube. There is some info that might be useful in this thread:

http://www.xt660.com/showthread.php?t=22771

The BMW may have 41mm forks, but that's the outside diameter, the important fact of the matter is the inside diameter and therefore what diameter valves will fit - the XT forks are 43mm O/D anyway, so unlikely to be the same inside. Whether they'll fit or not depends on whether the BMW has cupped top or flat top damping rods, and that I don't know (the XT has the cupped type).

__________________