SRT you have done a nice design, the dyno result is very impressive! But I have a quick question for you. According to some online guide, there's some experiential rules, said there's a best ID of pipe, fit about 60HP per inch^2 for NA engine， for best flow velocity.(
http://www.team-integra.net/forum/bl...sure-area.html)
I've read your exhaust uses 2.5" pipe, so I wonder without regard to owner's favor, if your shining head-back exhaust with the stock sized 2.1" OD pipe can actually get a greater power gain? or at least keep current gain(with a lighter weight compare to your current 2.5" one)?