My non-MoCo Harley service manager disagrees with that. He says, assuming the intake part of Stage 1 is done right, punching the stock mufflers helps the power. He says it's not as good as a properly made aftermarket exhaust, but much better than stock and as good as many improperly made aftermarket exhaust systems. I'm no expert.....just passing that along.olivier said:Suppose you want to drill the baffles ... no power gain by doing that, only noise. Better buy some cycle shacks (under 100$) new or have a look on Ebay when money is a problem. Good luck.