To mount the Kontronik 600 to the firewall I used a mount system which [link=http://www.espritmodel.com]Esprit Model[/link] (
http://www.espritmodel.com ) sells specifically for the K600 motor. The mount consists of a front plate, back plate, 3 standoffs, screws and optionally spacers. You can purchase the mount with standoffs in various lengths to suit your application.
I used 4" standoffs with no spacers. I have included pics below of the mount as it comes and assembled off the plane for illustrative purposes.