We do not recommend any performance mods until you have progressed to Yellow status, and maybe not even then. This is because there is still plenty to learn, and by modifying your car, it actually slows the learning process.

As long as the modification is not to try and make the car faster, that is ok. IE: 5 or 6 point restraints, racing seat, camera mounts are all okay.

Not a problem, keep what you have, but at least refrain from putting race tires on the car until you are comfortable with you car's dynamics. Street tires are much more forgiving than slicks and easier to recover if you get in over your head. Also, if you go off track you are less likely to hurt your car.