You see that a lot Sal and it isn't that the droning got better but rather the drone trained them to drive around it as much as was possible (keeping revs up or down so as to stay out of the drone range, using either lighter or heavier throttle, different gear, etc.) and they simply got used to what remained that cant be driven around. Please be aware I'm not calling you out here, an exhaust will change its character as the packing settles in and I have not heard this exhaust either before or after it has had some miles put on. Also I think everyone is aware that some people seem to tolerate drone quite well where others will be annoyed by even the slightest hint. Still an exhaust will nearly always got louder over time when actually measured with testing equipment rather than more quiet and volume is integral to resonance induced drone.
2012 E92 Space Grey with fox red/black/black, comp, premium, DCT, premium sound, sirius, heated seats.