@xNJLM The fastest car will always be the lightest car. This means that you
have to remove as much material as possible from the block that you get,
but remember to look at specifications well. The difference between a
winning car and a disqualified car is only a millimeter. You can look at my
website under 7th Grade and you will see a ton of different design ideas.
Good Luck on Race Day!
@techhahn Not necessarily. Although you have to take care to reduce weight,
aerodynamic considerations are important too. For example, it's best to
have a 'shell car', where you have a clean shape and concealed wheels, even
though shell cars are often heavier than 'rail cars'.