Has anyone installed the Nav V on the crossbar ( micro fiche drawing below) above the instrument cluster? The crossbar mounts via 2 screws, but it's not clear to me if those are self tapping or require nuts on the back side. I'm looking for guidance on how much tupperware disassembly I am facing to complete this task. At a minimum I know the windshield has to come off, and potentially some dashboard components.

Thanks in advance!