I didn't have to change anything else on it. I was definitely able to feel a good difference between the stock pipe and the aftermarket. No change in jets, adjusting of the air/fuel mixture, or messing with the airbox/intake. The guy who helped with the custom pipe was Mike at El Torreon Cycle in Kansas City. He builds and races vintage scooters, been doing it for quite a few years. He looked over whatever might need tuned, but said it was running exactly how it should with just a change in the pipe.