[MENTION=3563]TyphoonFiST[/MENTION] I bought it off the forum pre-wrapped. DEI makes gold and silver covered reflective foil.
There's a guy on one of the FoST forums that can source it as well. When I had my FoST I saw a 7deg reduction in charge temps using it on just the filter housing. It was especially helpful during hear soak in traffic.