Well, mine whistles really loud with my BHAF but it's mostly coming from under the hood. I'm sure there's some coming from the pipe but I'm always driving so I can't really tell. I know people always stop to see what kind of dump truck is coming their way but, when they look, they only see me coming....

 

at idle w/ my scotty II, and straight 5x36 you can hear the turbo whistle coming out the pipes. cant hear it down the road at all, because the stacks drown it out inside the cab, you can hear it whistle. i got to figure out how to remove my silencer ring though so i can hear it some more. i like as loud as i can. have driven from nc to tx twice, and tx to va once, and i dont mind.