So using the search function, it seems that you can replace an English BB with a BB-30 although it may not be reccommended. I have a Cannondale System Six that I am thinking of upgrading to BB-30 when i wear out my current setup. Someone said that Cannondale says to not do it for their carbon frames, but for their aluminum frames it's ok. Does anyone know if this is true? They also said most shops will do it anyway... Thoughts, criticisms, or concerns?