Ah the big Flowmaster love hate debate. I think what it strictly comes down to is are your ears too sensative to resonating noise? I dont mind it. However there are some people that cant stand to ride in my car with the Flowies.
Ya its loud and noisey but it also sounds like a beast that it is. Nothing like hopping on the throttle and giving the neighbor hood a blast! Now that being said if you stick Flowies on a relatively stock motor they sound like crapola. Get yourself a nice cam and some engine work they sound good WOT.
Flowmasters were never meant to be a quiet muffler. Even the representatives said that when they first came out. I wouldnt want them on a car I drive 2 or 3 times a week. On the Duster which makes it out to shows and such always attracts massive attention with the sound. I have had people come over to inpsect the big block under the hood only to find a paltry 360. So ya... I am pro-flow to a extent. If your using your car alot... go with the quieter sounding muffler. I dont call my car Shake n Quake for nuthin... ha. There is alot of exhaust out there that sounds great. Its all personal preference though... like paint color.
-RPM