The turbo quiets it down a bunch also. To the OP, like said, pipe size has a lot to do with it. Generally a 2-1/4 muffler is quieter than a 2-1/2, a 2.5 is quieter than a 3" in the same application. an X pipe changes the tone and seems a bit quiter than an H-pipe that tends to deepen the tone. Like most things, there is no single answer.