Could it be possible for you to go to a BMW meet somewhere and actually listen
to several different exhausts?
I can tell you one thing for sure, though: my tolerance of drone and loudness
is not exactly
the same as yours. So do you really want my opinion -or even from others- about exhausts sound?
-2015 F30 320i, Imperial/Oyster, 8AT, ED
-2012 E92 M3 Jerez Black/Rust Brown, M-DCT, ED: Gone
-2008 E90 M3 Melbourne Red/Bamboo, 6MT: Gone
-2007 MK5 GTI United Grey/Grey, DSG: Gone
-2004 E46 M3 Carbon Black/Cinnamon, 6MT: Gone