I just installed this mount / engine on a Sig Mayhem. I did nothing to the firewall and saw no reason to do so. After all the mount is supposed to eliminate the vibration forces ?? I was prepared for a lot of shake also - never happened. It moves a bit at idle and when you first hit the throttle but barely noticeable. All in all I like this mount. I also replaced the plastic mount and it is now much quieter / smoother with no ill effects.


I just reread the instructions and the ONLY place it says to reinforce the firewall is IF your using the ARI mount which incorporates a nose ring. Your using the "A" mount which does not. Your good to go.