From what I have heard you don't need setcpu to overclock with that rom. I have setcpu on just for the profiles as a security measure. It gives me a little piece at mind.
i agree overclocking bb isn't necessary to me yet at least i was running cyanogenMod for last 2 days and switched to bb last night and can tell a huge diff it feels much snappier and responsive and im only running stock 600mhz kernal