Bigger cp3 or socal heads?

This winter i am planning on putting some 60% injectors and head stud's. I have enough money to either do a bigger cp3 or possibly heads but was wondering which of the two would complement my setup the best. I know it would be nice to do both just can't afford it. I'm at 587 to the wheels now and want a nice safe 650-700 hp daily driver. I know that is pushing the bottom end but i wouldn't drive it around turned up all the time. If cp3 is the answer what size. Thanks for the help.