First, I would find an RC car that runs near 20mph and see how slow that feels. It is hard to get a 1/10 car to mimic the performance of a full scale car. While the size is 1/10th, the weight is WAY less. A 2000lb full scale care would weigh 200 pound in 1/10 scale. Our cars weigh 3-4 pounds. So, scale handling and performance is going to be hard to mimic.

Real car grip is greatly affected by the inertia of all that weight being thrown around. Our cars have 1-2% of the weight, so the physics don't scale.