Just guessing but it looks like the Arrow silencer with Cat would about equal the hp gain of just removing the Cat alone (keeping the stock pipes). And it appears the Cat is responsible for the 7K dip, which would be erased also. Anybody else see it that way?
I don't have a 04 yet, but I hope to soon. In the meantime I've been playing around with some dyno charts. I remember the huge difference a Akrapovic full exhaust made on my 99 R1 and am a little disappointed at their power gains for the 04. Arrow's dyno charts looked great in comparison, until I overlaid both charts- see below.
I've scaled them so the rpm matches and also to account for the ps to hp difference of about 1.5%. It's not exact, but pretty darn close, especially considering how well the stock systems line up... until 10k rpm! Sorry if it looks confusing, but if Akrapovic is to be believed, then it appears to me as though Arrow is using a restricted bike or faking dyno runs to make their exhausts appear to perform better. What do you all think?