First thing I would do (if you haven't already) is have it inspected by a highly recommended independent BMW-qualified mechanic. Ask other BMW owners in your area for recommendations. It will probably cost $100 or so, but will be worth it. If something is found needing attention, you'll be glad you did, and if nothing is found, the peace of mind is worth at least a Benjamin.
Congrats! Your engine and trans are just starting to break in. Would look at control arms, shocks, struts, and I hear, rear sub frame bushings (my next DIY), if not yet replaced. Also, your tensioner and serpentine belt, and also have that battery checked (the battery issues can cause baffling symptoms so be prepared).
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