Exzess discs are all directional due to the use of curve vanes. The rotation of disc will pump air from center of disc, through the vanes, and out through the outside diameter of the disc. Discs will be runing back from inside to outside diameters.
Drilled or slotted discs?
Both drilled and slotted pattern will increase bite and help gas releasing from friction material and fade. Drilled discs have advantage of being lighter and runnung cooler. Slotted discs are with a continuous refreshing of the brake pad surface. However, drilled discs are mostly not recomanded for racing application.
What is brake torque?
Brake torque also means braking power. Effective radius is distance from hub center to caliper on disc position. The force exerted by the caliper, which is determined by pistons size/area, multiplied by the effective radius equals the brake torque.
Which direction should the discs rotate? 
