More relevant is that it apparently came with a hollowtechII bb, which would indicate that it's a regular threaded BSA BB. 2008? Yeah, that makes sense. Cannoindale started that BB30 nonsense in 2000, but not a whole lot of manufacturers were using it yet in 2008, as far as I recall. Anyway, if it's a 2008 and it's got shimano cranks, you can rest assured you got a "brit" bb shell, and the gxp is your only option, out of those listed in the OP.