I was bored sometime over christmas and tried to fab up a heat shield, but when I was making my cardboard template I discovered it was way too hard, there is alot of stuff in the way. If you want cooler air in there, it is far easier to just duct some cold air from outside the engine with a hose. like this:
http://www.imagestation.com/album/?id=4290475231
but if you want to make a heat shield here is one from a S14 at the TAS
-Matt