But Forza 5 is a launch title and runs at a rock solid 60FPS.
I think Forza 6 will look better than PCars, now that the devs had some time with the final hardware.
It might, but I wouldn't count on it unless they've completely rewrote their engine, which is a bit too much to ask considering 2 year dev cycle.
As for performance again PC would probably have double the current framerate if you cut out real-time lighting, people in general underestimate just how much processing time it requires.