I've been considering drilling out the center hole as well. I already drilled the 4 1/2 inch holes in each muffler plate and it definitely added some noise, but more of a loud flutter than the roar I'm looking for. My only concerns with doing the center hole is the baffle plate that is cut coming of inside the exhaust and any marring that will happen inside the pipe and eventually rusting. Anyone got any opinions on those issues?