I just hit 5000 miles on my odo (first - paid- oil change scheduled tomorrow!), My exhaust seems louder in general, but I notice it pops more when it's really hot out (My Ducati also does it). It isn't as loud on start up as it was when temps were freezing, but Greg I assume you're talking about driving loudness? Maybe it's because I tend to drive with the windows down now that it's warm, so I can hear all the disgruntlement going on in those pipes
I smoked a brand new 535i yesterday, and the process was fairly loud too. The 5 owner seemed pretty pissed.
