First video is the dyno run. Second video is the printout from that run. Notice how absolutely perfect the air/fuel ratio is with the TBR exhaust. My guess is that it would be richer with stock pipes.
https://www.youtube.com/watch?v=j45Fb1r0agc
https://www.youtube.com/watch?v=oeADSzDwlWs
https://www.youtube.com/watch?v=j45Fb1r0agc
https://www.youtube.com/watch?v=oeADSzDwlWs