I notice that the front grill has a lot of plastic (filling in and blocking air flow thru the "mesh") is this for aesthetics or does it serve a function (keep out rain???)

 

The lower front grill does the same. Seems like a waste - or maybe for some extra lights?

 

I am pretty sure it is to limit the amount of air that gets forced under the hood at speed - as it is, it starts to shake above around 80 MPH.

 

Eventually I'm gonna fab an OEM look GT grill w/o lights and pony; I plan to cut out these blocked mesh areas; I think they might also be there for strength since this is all just plastic. I have CDC Agressive going on soon, so no lower grill (wide open).

 

Check the 4 rubber adj stops along the base structure below th ehood leading edge. Ford has not adj these well and this problem has been identified out here; plenty of folks running 100+ with no hood shake. I had to adjust mine (two were not making contact at all; use chalk or little rtv to check contact)