The way that your spark plug could have taken a (poop):rolleyes: is from running too lean from your ebay chip!!
Just to be sure.... maybe you can have bmwconnect on the list read your chip and let you know for a fact?? He tunes these things and many more advanced options than a stock motor. Just a thought. You surely don't want to start rebuilding a $3,000 motor for a $50 mistake right?
Glad that it was only a spark plug......
Cheers,
~Ralph