Yeah, does anyone know what those are, they rattle whenever my subs hit, and it's super annoying, I was thinking of sealing them up, but not if they are there for some important reason. Someone has got to know what they are for.

 

I believe those are pressure vents

 

They are to release pressure from the A/C system or when you shut your doors. Don't close them or your ears will pop when you turn the ac on, or close the doors.

 

how much of the raammat would be needed to cover the floor, backwall, and doors of an extended cab?