@scotth944 I asked a friend of mine who works for BMW AG about this subject. He also owns a 1M. He think its the design of the limited slip differential. It is true that the 1M is capable of achieving a 100% lock condition - but that 100% is only in theory. And when it "locks up" he told me that's when the rear axle (will)step out. He gave me this article on lsd types - it's in German, but you could use Google to translate it.
http://www.limitedslip.de/varianten.html
My friend also said that IF you were to take a 1M to track events or racing... he suggested to replace the 1M's LSD with another one that doesn't lock up so abruptly.
I also remember seeing an BMW AG video from a few years back... they tested various LSD types installed in various BMW ///M(e39, e46, e92, e60 and F10) models. I tried to find it, but it is eluding me right now. Maybe someone else remembers this video.