I showed up with a 917d3 with an aftermarket shaft that I have been struggling with tremendously. I have a high swing speed 112-116 and was only carrying the ball around 235. If I tried to add any extra power to it, the ball sprayed all over the course. I knew the math didn’t add up and it didn’t take long for the numbers to start getting better. By my 5th head/shaft combo my carry numbers were spot on 278-285 every time and the ball went straight more times than not. I’m not saying everyone will see my same results, but I promise, if your not playing with a driver fitted specifically to you, your losing distance and accuracy.