How do I put this best? Controls are fairly easy, WASD, Shift, Crtl is all you need. Controller support is there, I find it harder to drive with a controller instead of a keyboard.
Currently, there are four cars, each reasonably unique. Colors are customizeable to an extend (depending on which car).
While racing, there are powerups. The ones you would expect, two types of missle, mine, boost. Additionally there is a shield, an EMP-ish thing and a mashine gun. It is a combat racer after all.
Regarding the racetracks, I would advise you to watch a few videos.
Ingame music is drum&bass, it is however possible to put in your own music.
Performance wise, GRIP runs on potato to high end system. Just need to choose the appropriate settings.