Your comparison with a sports car is very appropriate.

Many cars have "race" modes which allow the computer to use the maximum power an engine has while not trying to force it into an "efficient" mode.

99% of the time you want your car to be as efficient as possible while others you want to see what it's capable of.

The Nissan GT-R does this automatically when you're located on a track:

http://www.engadget.com/2007/12/22/nissan-gt-r-disables-spee...