[cvos]

The main reason for the strict limits on car and engine design is safety.

It is possible to build an uncontrollable death rocket on 4 wheels, but this would simply be to dangerous for the drivers and fans.

If these strict regulations were not in place the teams would create cars that would be self destructive.

[bmj]

A good example of this is the heyday of Group B cars in rallying.

http://en.wikipedia.org/wiki/Group_B