If it is a direct copy of the Magnex, then it will be more free-flowing than any other off the shelf item. This is because it is twin 2¼" system, which has flow properties of just over 3". Also, because there is no issue with getting baffles in this size, there are no size reductions in the exhaust, unlike some 3" systems, where the baffles are smaller than the 3" bore.