I have been playing the 910 D2 with a stiff shaft. I was fitted for the 910 in 2011. In recent years, when I would hit a good drive, I would use an app to measure the distance. I consistently hit it 233 yards, a far cry from previous years. In 2014 I was fit for AP2's with regular flex shafts and figured it was time to change the driver shaft too. I recently was fit for the 917 D2 driver, with a regular flex shaft.
When I received the 917, I inserted the Surefit CG weight for fade. My natural flight is straight and like to introduce fade. Draws are very difficult with my driver. I wanted to eliminate the left side of the course, hence the fade preference. Wow, I never went left, and missed most fairways right. That CG sure works! After some more experimentation, I settled on the Surefit inserted for a draw bias. Now I can hit all shots! I finally have that draw on call, while still hitting straight or fade shots! And, my distance is much improved. I am now hitting 260-270 yard drives! Larger sweet spot? Likely. More confidence and faster swing? Likely. Proper shaft flex and better spin? For sure(fit) Ha! Ball flies off the face like butter, I love the feel and flight.
Oh, I tried other brands during my fitting. I didn't gain any more distance with them, and they didn't offer the adjustability that Titleist offers. You can see I don't buy clubs every year, so adjusting for my aging is a plus.
Very nice job Titleist, thank you for another great product!