If you are throwing 325-350 without a run up, I would go to a 3 step WALK up! I used to RUN up the box as well, and found that was leading to huge deficiencies in my accuracy. I now tell myself to go slow, smooth and deliberate on every teeshot.
I would go try a Discmania PD and an innova Beast. The PD is a speed 10 that's in my book, just a longer faster teebird. And the beast is a good under stable driver that has lots of different uses, like the Hyser Flip, anny, BH Roller...etc.
Some of those really wide rimmed discs could do harm to your game. Learn to throw fairway drivers, and maybe a Destroyer, and you will be just fine.