I have been using the titleist 983k 9.5% for a long time but feel as though its time to upgrade. I like the new 910 but dont know if i should get the d2 or d3 and my other concern is the shaft.  I currently have a Graphite Design YS-6 .335 tip (MSI 70) stiff flex and dont know what the comparable shaft would be for today's driver.  Several knowledgable people have told me that the stock stiff shafts are not as stiff as they used to be and recommended that i order the 910d2 with the diamana ahina 70 x stiff.   However, i wasnt sure if that was truly comparable or if the diamana ahina 70 stiff was a more comparable shaft.   Any recommendations would be much appreciated.