So in an effort to keep heat and other smelly stuff on the other side of the firewall, we painted the interior side of the firewall with this crazy ceramic insulation paint.  you can find the stuff here  http://www.lizardskin.com/pages/ceramic.php   I called the guy there and chatted with him, and I liked what he had to say.  The stuff is really light weight after it dries, and apparently it’s insulation properties are excellent.  I had already painted the tunnel inside area underneath the false floor, but I decided that I wanted to do the whole firewall.  Also, even though I sealed all the nutplates and side-skin to firewall joint with proseal, I like the fact that the paint seals all the rest of the cracks.  The paint is super crazy thick though, and requires a special gun.  It’s also messy.  Very messy.  It pays to thoroughly mask before you spray.  and we did.