AutoX/Road race in a dart??

The bigger brakes are very important once the car is fast enough to need them. Speed is turned into heat and the faster you go, the more heat you need to get rid of.

Also, the bigger brakes can reduce unsprung weight while still have more rotor mass because they can be built with aluminum hubs and aluminum calipers. The factory 11.75 stuff is really heavy. Here is a 13 inch Mopar setup using custom hubs and rotors.