No idea here man. I have the 2.5 inch header with a dynomax 3" muffler and a turn down. My exhausts stops right below the e-brake handle. It's loud as absolute hell, actually it sounds like a boat out of the water if you know what that sounds like lol. I'll be dynoing in the next month or so, and I'm going to put some gears on and just keep adjusting till it makes the most power lol.