So I think I fixed my issue with the car. My dad called BMW yesterday and they said the grinding sound is 99% most likely from the differential, and that doing a few quick figure-8 turns should eliminate it completely. Did exactly that and its fixed!
So I think I will not need to come over this weekend to get the issue looked at. However, I want to thank you for offering your time to help me out. Did you see my thread about the German Car Day at Larz Anderson? Should be a good time and would be cool to meet up if you came!