Stock-ish 5.7 Build...2.5" or 3" Exhaust?

So, by my calculation, not counting loss for bends and total length, dual 2.5" should be good for ~515HP. Even if one allows a 10% loss over the system, we're supporting over 450HP. As well, the exhaust becomes denser as it cools through the system, so by the time the bends are really coming into play, the exhaust is taking up less volume.

I thank you for that indepth reply. It's nice to have hard numbers to look at/manipulate...2.5" it is!