Regarding vane designs, our rotors have a patented curved vane which pumps a larger cfm per a given RPM than any of our competition. The air is pulled from the center of the rotor and is pulled throught the vanes and expelled out the circumference. Hence, the vanes need to end pointing rearward as they are mounted on the car.
Since our vanes are curved rearward, we slot in the opposite direction to maintain strength for the friction plate. You may also note that we slot altenate areas on the inside and outside friction plates so that the slots never overlap as well.
Slot direction does not effect performance. They can lean forward or backward without any change in mechanical ability.