Couldn't get mine to fit in the side panel along with the alarm - not enough room. Too much trouble to try & relocate the alarm, which is why I went for the option of fitting it behind the rad., lots of space there.
Owl I sure wish I had seen those pics yesterday morning. I removed all the radiator trim and couldn't figure how to mount there. I did mount it successfully behind the left side cove as Biker 1059 posted. When I was trying to locate it behind the rad I was pointing the horn forward. :?