Megaphones are used to make things louder. If you want quiet, you're already headed the wrong direction.
If you must use one because you like the shape, it has to be full of sound damping material like fiberglass. Don't use stainless steel wool, it doesn't do jack to attenuate sound. Basically you want a perforated tube running the length of the pipe, with fiberglass stuffed in the area around it. But with a megaphone shape you lose a lot because the packing has to be at least ~20mm thick around the pipe to really do much.
I don't know what your bike looks like but if you truly want it quiet, ditch the megaphone and buy a cylindrical shaped muffler with packing in it. And don't go overboard on how big the inner pipe is, the added restriction of a smaller pipe doens' tmake nearly as much difference in power as people will have you believe. Trust me, and straight through pipe will have significantly less restriction than a stock muffler.
If you must use one because you like the shape, it has to be full of sound damping material like fiberglass. Don't use stainless steel wool, it doesn't do jack to attenuate sound. Basically you want a perforated tube running the length of the pipe, with fiberglass stuffed in the area around it. But with a megaphone shape you lose a lot because the packing has to be at least ~20mm thick around the pipe to really do much.
I don't know what your bike looks like but if you truly want it quiet, ditch the megaphone and buy a cylindrical shaped muffler with packing in it. And don't go overboard on how big the inner pipe is, the added restriction of a smaller pipe doens' tmake nearly as much difference in power as people will have you believe. Trust me, and straight through pipe will have significantly less restriction than a stock muffler.
Now I'm trying to decide if I should start searching for an M900 or 1100Evo Monster as a new project bike... or sell everything and buy a toy car. But I digress.
