I hardly look at the age of a thread. Because the info within it is not only relevant for the original person but for anyone else in the future to read and take advantage of. Her is a Pic I found in a kart catalog I have to back up my answer to this thread. Stock or modified will benefit from a header. Not only this certain one but most all will have gains, and even more if steps are taken to tune for it instead of stock muffler i.e. jet size and or carb screw adjustment.