Red Bull races all the toys by yasirshoro95

Weight has nothing to do with air resistance, the lighter and heavier car will both experience the same amount air resistance when travelling at the same speed and the motors will produce the same amount of torque so they will both have the same top speed (the heavier one taking longer to reach it) since the forces acting on them are exactly the same. However, the heavier car may actually have a higher top speed from increased traction caused by its weight, only going straight tho.