I was confused also and said hell with it and bought these Blasting Bob's (3.6L V-6 Challenger w/4"x9" Magnaflow mufflers.) Installed in less than 1 hour and I'am happy, no drone and a bit louder. Exhaust is a personal preference, but I've gotten lots of (sounds good comments)when I hammer on it. Now the longer I've had them the better it sounds. Good luck in your exhaust venture.