[Racer x]

With lad speed racing weight is less important than road racing. In drag racing weight is critical.

With road racing breaking and acceleration are the key to better lap times. With drag racing it is a pure power vs weight to accelerate mass from a stand still to max speed as quickly as possable.
Land speed racing is power vs aerodynamics ss weight is not a big factor. Once the body is in motion the weight becomes less important or even can help as wind gusts can slow down a light object easyer than a heavy one.