I found this article regarding a 3 inch vs 3.5 inch exhaust.
3-Inch Vs. 3.5-inch Exhaust Test - Tech - Modified Magazine
I thought about maybe having a custom 3.5 inch made after reading that. I have a single 3 inch, and I seem to be getting some lower numbers compared to the other guys with dual exhausts. At 11 psi, I am getting 509hp when dyno'd in 4th gear. Anyway, do you have any input Sasha? Or anyone else? I wont be doing this anytime soon as I have spent waaay too much money on the car this year lol. Needless to say I have a lot of rear end kissing to do with the wife lol.