I wanted an answer from a bmw expert who had heard one of these cars before, if possible
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I have heard many of these cars before, I know what the exhaust sounds like.
I have not heard YOUR 650 to know what noises exactly you are experiencing relative to a "normal" 650.
as I said, with no light on, there is no misfiring, so I have to conclude it is operating normally based the information I have
as the question has been answered, please kindly CLICK ON a positive rating