the mufflers on my gxl have a rolled in finish on them, i was wondering if i opened them up so they are strait would the car be any louder? also do you think they might be retricting any of the air flow? the hole left after the roll is the same size as the pipe going into it from the muffler. id like it if it was a bit louder, its kinda quiet right now. heres a pic so you know what im talking about.

 

I would be surprised if it made it any louder and you definitely won't see any power upgrades. Yes, technically it is ever so slightly obstructing the exhaust gas flow, but since it is right after a cylinder that is larger than the muffler where its coming from, and given that its right next to the end of the exhaust system, I would be surprised if you got .0001 horsepower gain from it. If you want some slightly louder mufflers, check out Racing Beat's.