you can open inner side of your muffler replace packing and than tig weld back. it would only cost you let say 50 bucks for welding. an experienced welder should not take more then half an hour to do the welding. bike will look more authentic with original mufler.
not sure if the ebay offering is rebuild able
GMC on this site can help with this kind of work if you can not find someone to do the welding localy