Latest info... For 2014, BMW (and MINI) have reduced the interval from 15K to 10K:
http://www.f30post.com/forums/showthread.php?t=868291
And it's still synthetic and it's still covered under free maintenance. I'm curious what prompted this change, especially since you can have the same N55 engine in both older and newer models.
Also, after high warranty claims, GM realized they needed to recalibrate their oil monitoring system for more frequent changes on their 4-cylinder engines:
http://www.autoweek.com/article/2013...NEWS/130409904