for the GT - thats A LOT of aluminum to be getting hot and trapping in even more heat, just sitting over your engine
just think of your GT engine being 200d - over the course of a a year, the paint on your hood will start to peel and discolor real bad.
please correct me if I'm wrong, but A LOT of metal in the engine bay tends to keep everything else in your engine bay HOTTER, LONGER... wouldn't you think its best for the engine heat to dissipate instead of being trapped?
the GT and GTS engine top designs are quite different.