I took this for a spin last night when it unlocked as I had to relinquish my excitement before going to bed!
I'm currently using normal textures as putting it them on high was an instant +200MB over my VRAM limit, whereas normal textures, before touching anything else, was sitting comfortably at 1400MB VRAM. I turned a few other things up to v-high, left AA off for the time being, and didn't touch any of the 'Advanced Graphics' settings. So, a mix of high and v-high with normal textures and I was getting 80-110fps during the opening sequence. As soon as I gained control of Franklin I was still sitting pretty on 80-90fps. I want to push it harder as I obviously have enough GPU grunt, but my VRAM was at 1800MB at that point. Will see how it goes though!