Yes we developed it some time ago.
Dave's Rotrex supercharged iS200 developed a misfire at the last dyno day which transpired to be caused by a melted and blocked catalytic converter, so we developed the Katana high flow down pipe and hi flow cat on his car.
Daves car is running a lot of boost and so was generarating an unusually high degree of exhaust back pressure. Changing to larger down pipes and the high flow cat presented him with another 20hp or so.
We have paid for the jigs to be made so can produce the Katana down pipe and cat to order. We haven't marketed them yet because we don't have any pictures.