I had the same issue. I originally had a d2 with a stock diamana in it. The ball flight was way to high and the spin coming off the driver was causing me a huge loss of distance. I went to my club pro and went through an intensive fitting and ended up going with a d3 head with a Graphite Design DI-6. It was amazing the difference, my ball flight was much more penetrating, and the distance added was probably 15-20 yds. I would encourage you to go see a Titleist fitter and let them go through the fitting process with you!
Ryan Crysler, TPI GP3Senior InstructorButch Harmon Floridianhttp://Butchharmonfloridian.com