When I was sourcing out various bits before I took delivery of my new bike, one question no one seemed to be able to give a firm answer to was if the Adventure-Spec crash bars can be used alongside the BMW wind deflectors. In short, yes they do.
One caveat—it's a bit of a squeeze to get the fairings on/off with the wind deflectors mounted while the bars are in place. Not impossible, just requires a bit of flexing/manoeuvring.
Also, people have asked about them rubbing the legs/knees, for me they don't at all, I'm 5’9” with a 32” inseam (can't quite flat-foot the F800GS unless there is a pillion on the back).
Hope that helps someone!