I'd love to help you out with these Pro Circuits! From what I've seen and ran personaly as long as you stick with a decent brand name pipe you are probably good. I'd be interested to see specs on all the names you hear about ran on the same motor one after another. If you stick with the FMFs, Toomeys, Pro Circuits, etc, I can't imagine there is a huge difference in power like there is claimed from going to a CPI or Shearer. That's what I get out of all this anyway. Whatever you can get a deal on and looks good is what I think I would run. Unless you have a specific motor and have a builder tell you which pipe would work best.