My wife got me the Titleist 913 D2 driver for Christmas. I know she is pretty awesome. The shaft in the 913 is a Diamana blue S+ 62 stiff. My shaft in my old 912 is a Diamana Kai'li 65 mid stiff flex. Will I be able to tell a difference in these shafts? If so what do you think they will be. I love the Launch and spin that I have with the 912 now. Any comments or suggestions.