keeping the interior cool

[LSX69]

Ok, so im throwing some ideas around while deciding what to line my car with to keep the road noise to a minimum and keep as much heat out of the cab as possible. I'm considering a combination of dynamats extreme liner and dynamat xtreme to keep heat from coming through the roof and firewall. Now to my idea, i work in the roofing industry and as im sure a lot of you are aware of the radiant barrier has become all the rage in new homes to cut down on electric bills and the stuff works great. they now have a felt called polaralum which i have access to. i was thinking about putting it on the inside of the roofskin to help reduce interior heat. my question is if anyone has tried anything like this? any issues with paint blistering from transfering the heat back? just a thought hopefully someone can chime in. Thanks!

Jeff Loud