If you hit the ball after it has been dropped the second ball is definitely in play!! No matter what.., unless your original is in the hole. If you have not hit the dropped ball and your original ball was never OB or in a Penalty area you may correct the drop.Rule 14.5.
If you were in a penalty area, drop a ball and then find your original ball you may not play your original. I studied the KVC rule and spoke with the Pro where I play. He said it is all about KVC and to memorize when you can and when you cannot make a correction. Every ball dropped in golf is dropped with the i intent to play that ball (or you would never drop a ball). That's why there is only at the appropriate time an opportunity to correct an incorrect drop when it is dropped for the wrong reason, but if you hit that ball then you own that ball all the way into the green. Game over.
That is how it was explained to me.
For a driver you really should hit one with a monitor and see how you do. Going only by static fittings is just scratching the surface. Shaft choice is quite important when it comes to drivers. It’s really beneficial to try one out before making any decisions. At least you want to know your swing speed. Then you start testing based on that. Shaft flex varies from one manufacturer to another. Cheers.
All driver faces, that are legal, have that .83 cor rating, assuming the golfer hits the ball at that .83 location on the face. . That means you don't gain any noticeable distance just off the club face itself, no matter who makes it. .
The correct loft of the driver head, along with the correct shaft for the individual golfer's swing characteristics, can increase the golfer's distance. This assuming the golfer has been using an ill fitted club head loft, and shaft to begin with.
This why it is best to get a quality fitting. A quality fitting will tell the golfer what loft, and shaft they need to get the best ball spin , and trejectory based on their swing speed, for their best carry distance.
This is how I understand a good driver fitting. I may be wrong, and there may be more to the math involved during the club selection process.
We see these advertisements that this, or that new, $500 driver will give the golfer 15-30-40 more yards. It might for some golfers, if it matches their swing characteristics. It definately won't give "all golfers" that extra distance.