It's the Tailgunner exhaust, from the same guys that make the Gatling gun revolving exhaust you might have seen on OCC.
I saw it, asked Sam if he thought he could make it work. I ordered one sent it to him and after the Maestro perused it, he deemed it worthy of being welded to his pipes.
One caveat, IT IS LOUD. I went from TORs to this and find it obnoxious. I hope through tuning and possible mods to quiet it down some, but be warned. As there are NO internal baffles or discs, save for the end turbine plate and the steel bracket it bolts to, there is serious noise generated.