In a somewhat comical update I did get another new OEM catback installed, this one also started rattling after just a few days, right in that 1800-2200 drone range that the factory catback almost completely filters out. It's funny, my original one definitely did not do this, I drive around with the windows down all the time and these new ones just are not happy on my car. I did tell my dealer and they are like well what do you want to do??? I told them nothing right now. I mainly just wanted to document it I guess for future reference.
Needless to say I did just order the Z-automotive inactive exhaust kit, hope to have that installed by the end of the week and be back to clean exhaust sounds again