[Mario_Marques]

I have one idea for people who blocks the front grills...
If you block, the heat exchange of the radiator will be reduced, so, you could wrap your exhaust manifold to insulate the heat of the exhaust.
you could also wrap the intake manifold to be sure your engine it's breathing cold air, it will help to keep the engine cold, or less hot.lol
I hope you guys understand(my english is not very good, please feel free to correct my words or sentences, it will help me to improve myself).

And another thing, if you wrap your exhaust, the exhaust temperature in the pipes will increase, it means, the exhaust gaz will flow faster because they are less dense(thats one of the reasons why sport cars use stainless steel exhaust).