I'll chime in as well. I HAD a drone at first like others have mentioned. I wasn't happy. I continued to drive it to "break" it in but tried to figure out what was going on. I also have the bypass pipes and the included clamps with the pipes were not sealing very well. Started a search and ended up with some clamps that both seal the joint but also add some mass. The result, no drone
Much happier now!
The rear is now lighter and breathes much easier without the secondary cats!