A sample from the products for the Muffler(s) include: Bolt,flange,8x38, Gasket,exhaust (nas), Stay,muffler, Bolt,8x28.
In this schematic the "Nut,8mm" is used most often.
The most reasonably priced component used on the Ksf90-acf Kfx90 2012 Usa Muffler(s) is the Bolt,flange,8x16.