Myself and another guy from this site are in the process of puting these two pipes to the same test. He had a build done by one very reputable builder and I had my motor built by a different very reputable builder. If you ask us, both of them were/are great people to deal with for different reasons. I guess you can say we both really trust and respect our builders. Overall, we had similar builds done. My builder has offered to do dyno tests on both of our quads using both the Rossier and Motoworks full systems and let the proof be in the pudding. Who in their right mind would turn down an opportunity like that? We will have some numbers for you within a week or two.