I have the Stebel mounted under the right hand side fairing and just need to do the wiring tomorrow. I don't anticipate any issues with that as I bought the wiring harness from Murph when I got the horn.
I took at 4" T-brace, cut off half the top, bent over the other half and mounted this to the two small supports for the heat shielding foam. I would have used an L-brace, but they didn't have one the right size at the Home Deport that I stopped at. A picture is attached.
I then took a small L-brace, trimmed off one leg about half way, and mounted it to the upper rear view mirror bolt. I had to grind off the corner a little due to interference with the structure, but it is a pretty solid attachment point. A picture is attached of that also.
Then I took a piece of aluminum angle, used it to connect the two brackets, and mounted the Stebel to that. It's a pretty stable platform. (The last picture.) The horn doesn't touch the ram air ducting at all. It does look like it will give the rider a pretty good blast when you hit the button, but I'll see how I like it for awhile before deciding if I want to break it into two components and mount the actual horn so that it isn't so confined.