Removing plastics from wheels is more for bringing in more flex that does provide more grip.
For stock racing you can find smaller spurs but most time they need to be used with larger pinions because the large diameter of the motor requires a certain choice of pinion and spur for the hart to hart distance of pinion and spur. But have people ever thought of the influence of the gyroscopic effect of high revs motor and spur gear on the handeling of the car?