Hi,

I would mount the module on the back side of the firewall on velcro. Clean both surfaces (firewall and ignition) with alcohol and let dry before sticking the velcro to the surface. The velcro gives good vibration isolation and the module is open to the fuse air to remain cool. I would notch the upper edge of the firewall for the spark plug wire and protect the braid with that spiral wire guard where it lays across the firewall notch.

I use velco mounts on all of my 3W modules with no problem as long as the mounting surface is completely clean before sticking the velcro on.

Elson