Not sure i can help you here but the majority of drone is produced in V4 mode and if the muffler is chambered it will amplify the drone.
Everyone has a opinion of what is loud and what is too loud. I have a 2014 SS camaro with a cat back american thunder flowmaster system which came on the car when i bought it. In V4 mode it was similar to driving on the rumble strip at 60mph. Freaking unbearable!!!! needless to say i got a SCT tuner disabled the AFM and a custom tune, And now i love it.