[Cbozz]

I ran OEM exhaust with catless setup and there is no drone with OEM exhaust.
You do need to hold the back nuts when you tighten the bolts otherwise those will spin... there is your problem. You should go over every bolt in your setup and make sure it's tight and jack up the car while running it and maybe someone revving it and see if you have any leaks... just feel it with your hand or if you can hear it... besides drone is not metal on metal but it sounds like woofing bass! Cabin bass that will rattle your change in the center console... good luck