I have seen them on cars but does it really work? any?

http://cgi.ebay.com/ebaymotors/AIR-F...QQcmdZViewItem

 

I have no idea, but just using my common sense, it would seem that attaching that to your filter would reduce air flow. Plus its just a thin piece of metal, the ambeint temp around the filter is going to be basicly the same, even if there was something hot next to your filter, it would just heat that metal up anyways.

 

and unless you have a short ram intake (most dont), your filter wont be near anything hot anyways, down behind the bumper.