I've only seen those on European bikes, mostly German. I don't know of anyone that makes something similar. They look like just replacement mufflers, as the headpipes and front shields look stock. I really like the looks.
Welcome to the forum and sorry for not being able to help. You might just look for similar mufflers and cut yours off. The top unbolts but the bottom is welded on.
Welcome to the forum and sorry for not being able to help. You might just look for similar mufflers and cut yours off. The top unbolts but the bottom is welded on.