Update: Turned off Multiview I missed the picture quality sacrificed in the name of framerate, so turned off Multiview. Put all the settings back on full and increase AA to Level 3 for the same framerates. Monitors are now in a flat plane instead of the wrap-around. Now before anyone says that is a step backwards, know that I'm using TrackIR, so I can turn my head a little and see the cars next to me. I've got the TrackIR sensitivity/speed turned down a lot because, hey, my window on the world is 6 feet wide!
I went straight-line with my monitors many months ago to gain the FPS. I'm perfectly happy with it. IMO it is a good trade off. You don't lose any immersion. It's just that the shape of your window to the virtual world is a little different. Mainly at the periphery. One other benefit is that straight lines never kink. With angled monitors, only the horizontal line (buildings, walls, guardrails etc) at exact eye level (centered vertically) are not kinked at the junction of the monitors. Repositioning your head height will mess up the view.