Greetings, I was hoping for some advice with regards to a brand new 535i with xDrive. I've noticed the left tip on the muffler has a black coating absent on the right tip. On past BMW's I've owned, I'd suspect an issue with the oxygen sensor on the bank feeding that chamber of the exhaust. I have not noticed any smoke of any kind (I followed the car while an associate drove it, at times hard, for me). This car is far more complicated, however, and my first foray into forced induction. I was hoping to get an informed opinion before taking it to New Country BMW in Connecticut (place of purchase). Do you feel this is a cause for concern? If so, do you have any advice on how to approach it to not get it dismissed at the dealer? Thank you for your time!