This whole subject is like splitting hairs. None of mine were bad stock. Every mod that improves air or fuel makes them louder. I yanked that dirty, nasty **** off my hood and that added tons of noise.
The newest obs is 20 years old. Even stock they are going to be noisy and clattery pieces.
I like them. Cool trucks. I like my sd 7.3. Cool trucks. Both old pieces of garbage though