Not sure what car you have, but I have first hand experience with the GXP heat soak. The engine compartment is basically sealed, and its all motor so the entire compartment is hot to the touch. I'm not referring to overheating hot, just stupid design hot. Racers have been using this same trick for decades to reduce under hood temps by shimming the hood, it works. The only real way to avoid it is hood vents, something this series did not come with. Either of these should be able to be fitted, and would work. It would all be personal preference.
http://www.ebay.com/itm/321819697588...%3AMEBIDX%3AIT
http://www.ebay.com/itm/331806233670...%3AMEBIDX%3AIT