For the neutrios link guy, their ability to go faster was disproven. The bulls is like "unstoppable force meets immovable object." Unstopable force would have infinite kinetic energy, and the immovable object, infinite mass. Neither can in any way exist in a finite universe.
With the speed of light car one, the headlights would shine out in front like normal because the speed of light is relative to the observer, any an all observers will view light goin the speed of light.