it's mainly there for sound absorption-i stripped all mine off cause it had soaked up a ton of injection oil etc over the years....just get some foil tape for heat protection @ the pipe area (where the foam is on the hood now) + make sure all your exhaust springs are actually holding your pipe where it's supposed to be-not the hood foam (especially if it's rubbed and /or burnt lookin) ....cause next time ya go for a quick rip your pipe might burn thru your hood it makes the hood lighter and easier to clean up the underside and it makes it a little bit more flexible (not that these hoods fall closed properly everytime anyways)just my 2 cents