lol, u wont unless u remove the whole resonator system, its still dimming the sound, and any sound that is there is being directed out the holes to the ground
remove the whole reso box and leave the approx 3" hole thats in the filter box there and it will make a sound difference, but it will sound crap and hollow cos its a massive echo-ey box
if u want growl look elsewhere into pods or smaller less echoed setups