Hi, Someone can help me in a doubt

I have an Team orion CRF ABI 5 PORT, I have read here that the best pipes are 2058...or 2013

so my engine came with 2057 pipe , and also comes with the header/pipe extension , i just used one time, i choosed to run with the extension just because i read here that this pipe doesnt have to much botton end power so due this i used the extension to longer the pipe and have more botton end power, its the better way to use this pipe? with the extension? , just asking again because i have read here about the lack of power from 2057 and nobody says about using or not using the extension, Or using the extension fix the lack of power from botton end?, what the difference from this pipe "2057" to 2013, i have a bad one pipe? this pipe has more fuel milage than others?

Thanks for the help