was googling to find what else is ot there now that i am preparing my bike and found this company. very nice quallity. i will mail them to tell me the headers diammeter and inlet outlet of the muffle
http://www.moto-works.jp/k_factory/muffler/yamaha.html#y6
http://www.moto-works.jp/k_factory/muffler/yamaha.html#y6