I ran a 5w-50 Castrol which can be bought at any pepboys when this happened to me. Lucky it was just a thousand miles before my oil change was due so no harm done.
2013 M3 Coupe-MR/BLK ZCP, identical to my 2011.
2011 M3 Coupe-MR/Blk
2007 Porsche 997C2S Speed Yellow/Blk sport seats
2004 BMW M3 Imola/Blk