Having owned a non M-Sport 650 and now an M-Sport 650 + X6 50i, I can say with certainty that the M-Sport does have a meaner, louder, more distinct growl very similar (if not exactly like) to the X6 50i.
The non M-Sport 650 was very tame sounding. I heard more engine clanking and ticking than I did exhaust, with the door open. The only way to hear the non M would be if you were standing directly behind it. More so on a cold engine but once the RPMs come back down, it was quiet again. The M-Sport exhaust on warm engine in idle sounds tons better than the non M at high RPM. Lol. The M-Sport exhaust note is just nice and grumbly all the time.
Southern, you will be hearing from my attorney for copyright infringement.
I kid, thanks for using my pic as an example
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BS about the whole Shadowline thing for 2013. I had to pay extra for the special order but no where near as much as $1500 for a post delivery price. I say we all petition BMW to retrofit us with soft close and Shadowline at original cost.