I have two Titleist D2 drivers and four factory stock shafts (all Diamana Blue)
Two of the shafts are supposed to be "regular" and two are supposed to be "stiff". Well, they are all different. One of the regulars is firmer than the other (almost a stiff), and one of the stiffs is firmer than the other (almost an extra stiff).
I'm just saying this to warn you that "stock" shafts have a large variability and one may work for you but not another.