I'm thinking about getting the flowmaster American thunder cat back w bbk longtime headers and a bbk shorty h pipe. I've watched a bunch of sound bites online of exhaust and found I'm a huge fan of the deep muscle car growl. My question is....the cat back I want comes w the super 40's mufflers and I was wondering if there would b a big difference If I got the flowmaster series 10's. If anyone has this setup or mufflers please show videos. I was also wondering if anyone knows if with American muscle can u swap the mufflers out in ur order and just pay the difference or do u have to buy them separate and b stuck w two sets of mufflers?