My last car was a non-MPPSK F30 340i.
When I picked my M340i up 2 weeks ago, the exhaust impressed me a lot. In Sport+ there were nice bangs on upshifts around 4-5k RPM and much louder burbles and pops than my last car.
At around 400 miles these exhaust characteristics have disappeared completely. Now the car sounds like an F30 340i when I let off the throttle, burbles are very quiet and muddy
When the engine is cold the exhaust goes back to sounding good, but within minutes the engine warms and the burbles and upshift bangs disappear completely.
Anyone else with a couple hundred miles on their M340i observed the same thing? I remember my F30 340i was usually slightly louder burble-wise when it was cold, although I don't recall the exhaust characteristics changing significantly in the first 600 miles.
5/6 update: I'm now at 900 miles. Been filling up with 93 at no-name gas stations but finally put a tank of Shell "V-power nitro+" (wow that's a lot of words) in my car. It sounds awesome, much more burbles.