MY guess is that some of the chainsaw engines are ported for high power. Of coarse a person can always enlarge, polish match carb and gaskets to intake better. Anything you do to get the fuel/air mixture in the engine better and out with a good exhaust system will help performance. Tunned pipes can really help too. I wish more was offered in the way of super good and lite exhaust parts. Also they got to be compact as possible. Thanks Captinjohn