Interesting observation.
The cars feel like they have alot more Grip @ higher frame rates.
It feels like one can attack a corner with much more conviction at 500fps.
At 60fps, it feels like, you're not really sure where the car is steering towards, and one's instinct for when to countersteer is vastly blunted.
At 500fps, even on a 60hz display, the handling just feels surefooted. On a 165hz display, it's even tighter.
Of course with Tp4 cheapo graphx card, visual fidelity are reduced significantly to hit those numbers.