I wouldn't use the 2 1/2 in your application if your looking to get the most out of your motor. We haven't even had very good luck with flowmaster using them vs same size in another brand. I broke all the baffles out of mine with a 600hp small block and 3" flowmasters, and my buddy picked up 4/10 in the quarter switching to another brand that was quieter under normal driving. Not knocking flowmaster, but thats our experience. If you don't care about getting the most out of your motor and like the sound, then buy the ones you like. IMO you should go 3 inch and find mandrel bent pipes.
