Im up til like four reading forums haha.
The foil pad is for resisting heat at the turbo. The exhaust in your 300E goes down the exhaust manafolds and out underneith the car.
In the turbo diesels, it comes up from the cylinder head, to the turbo, then out down back to underneith and out of the car, so there is high heat concentration near the hoods surface.
Look at that webpage, you should be able to figure out what I am trying to say.