i have two mtx thunder 6000 in an undersized sealed box (looks like a box for two eights, good thing tho is i still have room in my trunk)..and a rockford fosgate 500 watt amp powering both...BOX IS EVERYTHING! i have some friends with some lower line products than me but with a bigger and better box and it hits better and bassier than mine. My question is can i just stuff polyfill/cotton in the back of the speakers inside the box to compensate for sound? I heard it makes the box appear as if it were bigger..and it slows down the sound waves..how much should i stuff? till its packed? or loose? thanks yall