IMO the real advantage to disc brakes is that they will not fade with heat as quickly as a drum brake will with repeated braking. Drums will lock you up as quick or quicker due to the rotational turning of the drum pulling the shoes into the drum tighter which not true with a disc set up that relies on pressure to push the pads into the rotor. For racing I know of several stockers that use drums for weight advantage and less drag than OEM disc set ups.