well I've rode a couple times with the new pipes on and I can say they are keepers. Bike runs great and sounds fantastic. Not excessively loud but a very nice tone. I'm no expert so I can't say if it has any more power but it definately doesn't have any less.
Do or Do Not... There is No Try.
2007 919...Delkevic Stubbies, Carbonfiber Hondaline Wind Screen, Integrated Blinker Mirrors, Brake Light Modulator, Headlight Modulator(soon)