I can offer a little insight today because I went the other way with pipes. I removed a pro circuit pipe and spark arrestor, and replaced them with the stock unit. THe stock pipe is less noisey, it sounds like a trials bike now. low end is a little better, mid range is close, and top end is much weaker. My bike has stock jutting, when the Pro Circuit went on it needed a little fine tuning, but never got it.
One other advantage to the Pro Circuit is that it weighs about half what the stock pipe weighs.
Also my Pro circuit pipe did not have any Orings in the lands as the stock pipe does. Are Orings used on the Pro Circuit? Do these burn out after a while? I like the Pro Circuit pipe, but wife prefers the stock set up. If you are doing all tight woods riding, I think I would prefer the stock pipe as well.