ok, so i am seeing that no one has actually seen behind the panel where the subs are. there is a black box that has 2 6.5 inch speakers in it. the box is held in by two bolts sticking out and three bolts on the top. the holes in the box for the speakers are made for those speakers only. the chances of modifying the box for an 8" sub are fairly slim. that's gonna be a pain. it would be better to just make a custom box. that is just my .02 though. good luck and post pics when you decide what you are going to do. thanks.