your exhaust become very loud especially if u using 5zigen bordermax or spoon.
the holes is to allow sound to pass through them and the fiber surrounding it to absorb that sound... to make it quieter,....the more holes...the more quiet it is...
u want loud is it?? then setup centre box only and no rear muffler... just pure pipe from centre box/bullet to the tail...
thats how my car is setup... heres a vid of how it sounds during a dyno...
YouTube - Banshee's Screaming Dyno 29012011
should be loud and garang enough...heh heh heh...
im using V-AFC :D
its GT Auto but i think his name is thomas... :P
that day was a group dyno day.... so i tumpang abit to get cheap cheap price :P
mine is stock B20 bottom + B16A head.
need new higher compression pistons though...compression with the stock B20 pistons not high enough.