I'm stumped between the flowmaster american thunder system or the mac. I originally wanted to go with the flowmasters because I'm a big fan of agressive exhaust notes and love the metallic muscle car sound that flowmaster provides. I've never seen or heard a stang with the macs so I can't compare the two. I was told the flowmasters are all sound and no go. That they're too open and don't provide enough back pressure for a good hp increase. Not sure how true this is or not but I've been recommended the macs by more than one person. I also like the fact that the macs come with an optional 3.5" chrome tails. How do the macs compare to the flowmaster or vice-versa as far as overall performance? What difference is there in sounds between the two? Additionally, I plan on installing mac full lengths and pro chamber h-pipe along with the cat back. Like I said, I'm a big fan of an aggressive exhaust bark and don't want my car sounding like an F-150 with 2" dynomax and likewise run like one. Any info, feedback, or suggestions are appreciated.