I agree with MinnFlyer 100%. I doubt if the additional strength would even be measurable. Think about the effort and the benefit.

Having said that, I alway paint the inside and outside of my firewall, landing gear mounts, and wing saddle with 30 min epoxy thinned with lacquer thinner. I also cover the outside of the firewall (after epoxy) with covering. It looks good and is very fuel resistant.