speed pipe

im Kinda New to building Motorized Bikes and i was wondering if anyone has ever used this pipe http://www.ebay.com/itm/47CC-49CC-MUFFLER-EXHAUST-PIPE-MINI-POCKET-CAG-BIKE-SCOOTER-EX27-/160724971356?pt=Motorcycles_Parts_Accessories&hash=item256bf46f5c&vxp=mtr I know Its for a 49cc But since...