Protecting the interior of the cowling from radiated heat is a big deal, especially if you have a turbo under there acting like a big piece of charcoal.  We used a product called Zetex 800 Aluminized to provide protection on the lower cowl of the Eagle540 installation.  (Lots of other Lancair guys have used this material as well for the same reasons with both the Lycoming TSIO540 and Continental TSIO550 installations.)  It's a pretty expensive alternative, one that required us to put together a group buy, of sorts... one guy worked as the coordinator to purchase the 50 yard roll (minimum), everyone bought their 1 or 2 yard orders from him.  Take a look at the Newtex website (http://www.newtex.com/home.htm), they're the company that manufactures the product.  It's basically a glass fiber cloth with an aluminized surface bonded to one side.  We applied it with red (hi-temp) RTV silicone sealant to anyplace that was subject to directly radiated heat (ie, sides of the cowling facing the turbos, undersides of intercooler ducts that face the exhaust manifolds).  I thought I had some photos that showed the installation, but apparently I do not.  I'll try to take a couple tomorrow and send them along.

   <Marv>