My current combo...Mac full lengths, Dr. Gas X, Magnaflow catback, on a 347
There are louder mufflers, but trust me it gets old. Eventually you get sick of it sounding like open headers and you start wanting not just loudness but tone and sound quality. Not to toot my own horn but video doesn't do my car justice. It sounds crazy in person. Cruising around it's mellow like a kitten but when you mash the gas things get rowdy fast. No highway drone either.