Ok, I have a 2-1/2" muffler right now, its rated at 11xx cfm. Problem is that its 30" long. I was looking at the catalog and the same muffer just shorter has the exact same flow.. shouldn't a shorter muffer flow more than one twice the length? I know the muffer that's on the car right now is too restrictive because I had an exhaust leak right before it and I gained an extra lb of boost. And the hole was only slightler larger than the size of a nickel.

Maybe its time to go 3"

 

IF YOU HAVE A TURBO YOU CAN NEVER BE TOO RESTRICTIVE im hoping you would at least go 3"+