If it is the header/cannister often associated with many of the 50cc-62cc chinese made engines, and sold by many distributors now selling the chinese engines, I hear they drop RPM a couple hundred, but significantly quiet the operation. Most who have them feel the price, and sound makes the rpm loss worth it. You'll spend more money on a header/cannister/pipe from K&S, MTW, Greves, etc...but generally the power improves, and sometimes greatly