This is a tortoise and hair story, but the fable can hold true. If the driver likes the feel of his car and runs a nice smooth lap, like the tortoise, he can outdistance the fast running hair. Much of what is needed for a fast lap in road racing is learned in testing. If a car has too much torque and is spinning the wheels, the crew may elect to change the intake manifolds. By using manifolds with a smaller cross sectional area in the ports, the engine is slightly restricted, reducing horsepower.
Headers can also change the foot-pounds of torque available.
By changing the exhaust tube lengths, or the size of the collector, engine harmonics are affected. By reducing the collector size, less exhaust is able to exit the pipes. If the tube lengths are altered, the waveform of the exhaust changes. The goal is to have the timing of the wave just right, for when the exhaust valve is open. Think of it as if you were swimming in the ocean.