the bk2 ferrule is not the same material. design is pretty similar, but they are using the much harder and stronger aegis 2 instead of titan/maxlite. also they have a thick carbon fiber pad to further strengthen the front end.
AFAIK about the fat shaft, it is made from the same blank as the 314-2, so yes it is just a fatter version of the 314-2. I thought it would have been better deflection wise if they could have increased the width of the bore since they have more diameter to work with. But that would probably take away from the more solid feel which they were going after with the fat shaft.
