Originally Posted by niznai

The speed difference depends on more than just motor power. Sure, all else being equal (disregard track layout) theory says the ligther car should go faster. But then considering the oversimplification about track layout you will see that only large open tracks will translate in significant differences in speed between lighter and heavier cars. But with a difference of say 100grams I don't think you'll a higher top speed or acceleration. Not high enough to beat somebody else's better speedo/motor/car design etc.

And about speed and crash, well, I think you're wrong again. Energy increases with speed squuared whereas it only increases with mass linearly. So a 1% increase in speed translates in a much higher impact energy than a 1% increase in mass. And it's impact energy that does the damage not g forces, etc, etc.