First of all, yes the stock muffler is very restrictive because it has alot of dead ends and such to keep it quiet and when I changed out my exhaust (catback) entirely w/ 3" and Magnaflow muffler, I noticed the engine stay cooler typically. But the other bottleneck is the actual piping, the stock CAT is 3" and then reduces down to 2"-2.5" dont remember exactly, so its a combo of the piping and the muffler. And you can do cherry bombs, but its basically open exhaust and cops like to give tickets for those. Just get a free flowing muffler like Magnaflow or ...damn there'* another one that is basically a straight pipe that is somehow legally called a "muffler". Usually its not a good idea to put a Flowmaster 2 chamber or anything like that because you got a V6 engine and it will nothing more than that, you will not get that V8 rumble or roar. I hope that kinda answers your common questions and future questions that tag along w/ this question.
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