The talk of my country club is the Krank driver. One particular member has the latest Krank driver model that is black and lime green with hexagons on it. Honestly, he hits the thing about 325 yards, on the fly. Now that others are seeing him hit the driver over three bills they want to pipe a few out there with him. Unfortunately, it is not just the driver that determines driving distance.
If you are hitting a Ping, Callaway, Taylormade or Titleist driver over 300 yards you may get a 5% to 10% boost from the Krank but your swing will determine the distance of your drive. In all reality, if you are hitting the ball 300 yards and it is in the middle of the fairway there is no reason to consider making another driver purchase. In fact, you would be stupid to consider changing up what is working for you.
If driving distance is your main concern and you do not care about scoring you may want to consider the Krank driver. You can find new and used models on eBay for between $150 and $350 depending on the condition of the driver. If you want the newest model Krank driver (2016 edition) you are going to have to pay a premium.
Unless you are playing the tips at your home course and it plays over 7200 yards there is no reason you need to hit a driver over 325. That said, it is nice to stand on the driving range and hit it all the way over the range. Imagine bringing that thing to TopGolf and hitting it over the fence at the back of the range.
Have you considered buying a Krank driver? What type of shaft do you want to put in it? What length would be best for you?