I noticed the same thing on my 2003 X5 3.0. I think it is more of "breaking in" than maturing.
2008 Space Gray Z4 3.0 si, Saddle Leather interior (to haul A$$)
2011 Nissan Frontier King Cab (to haul crap)
2010 Lexus RX350 (to haul people)
2009 Club Car Precedent (to putter around the beach)