Have noticed that the big plastic lid that sits on top of the engine gets seriously hot. Now on the basis that this is actually the air intake system i have to assume that the air being sucked into the engine through this lid must get very heated on its way through the intake assembly, and engines perform better when fed cold air. Has anyone tried insulating the 'lid and intake pipes' from the heat generated in the engine bay. If yes, what did they use and did it make any difference. I do not want to fit a cold air intake as I do not want a loud intake roar.

You have a solution looking for a problem.

Very well tested by Mercedes, no problem exists.

I'm pretty sure they engineered it that way. Well, as far as the material choice. The plastic is going to dissipate the heat much faster than anything else. I don't see a need to wrap it, install a cold air, or anything for that matter.