I went in today for fitting and was surprised how much better a shaft suited for my swing helps. I took 2 of my drivers in
TP 8.5 burner matrix shaft
909d2 with a graphite design stiff
For me the burner was the wrong launch angle. I dont remember spin and angle numbers but I was getting 250-260 with another 20 yards roll.
The Titleist was more spin and high launch angle. I was getting 260-270 with another 15-20 yards of roll.
My swing speeds was around 103-105 on his monitor.
He determined to change the shaft in my titleist because of the torque in the factory shaft and the shaft was not stiff enough.
I gained another 20+ yards from the change. But what I really liked better than that was my shots were not all over the place. My shot pattern tightened up.
I hope this helps. Because he sure helped me today.