a expansion chamber will give you a better sound for sure but i dont know about a noticeable amount of power but it will increase HP it is one of the best upgrades you can do but you may want to go to a NT speed or a dax RT carb to give you the full affect of the expansion chamber as far as the sprocket goes it depends on where you live if there are alot of hills it might be more of a burden than a asset since it will rob you of torque if you live somewhere thats fairly flat it will give you a nice top speed im going to put a 36t on my bike in the morning because im not in the hills to often and ride fairly far and the reduction of RPMs would be nice for me
