Well, I'm back after my tests and I can definitely say that my performance remained the same for me.
The good news is my baseline performance is already where you other GTX 970s owners are reporting. The bad news is optimizing my game basically left me at the Ultra preset, but then it enabled Screen space reflections (was off), 2xAA (was on MLAA), and set my Shadows to Extreme (was Ultra). 2xAA and Screen space reflections are very taxing, so my framerate at the campaign map halved. When I manually reverted my settings, I got the same exact figures. Campaign map ranged from 72-86 fps, and my quest battle ranged from 53-60 fps. The overall difference between my before and after optimization was an improvement of 0.4 fps on average, which is well within the margin of error.