I know on a dyno sheet there is a difference, but I bet it will be very hard to tell the difference in the seat of the pants. Unless you put a total shit 2-2 on (like samsons with fishtails) I don't think you will notice. you just need to decide what you want. Pipes are bought on looks, sound, and power potential. Everyone places those 3 things in a different order. Just need to decide what is most important to you and go with it. I feel I got all 3 with my Bassani Road Rage, but many think it's the ugliest and worst sounding pipe on the market. to each their own.
Zach