Wouldn't then all the heat from the engine emanate into the passenger cabin, making your interior feel like a sauna?
Have you ever taken your engine cover off after driving the car for a bit?....the metal cover itself is hot (and that's even with the honeycomb heat shield underneath it). Not to mention you will probably lose hearing after a while as there's no more sound deadening carpeting either. This isn't another stir the pot kinda post of yours for amusement is it, cause if it is, I think you should also remove the heat shield behind your seats for some extra sound and heat ventilation enjoyment.
Have fun with the project, and let us know how you make out!