What? LoL
I think you know what your talking about.. just can't word it properly..
Vortex generators simply interfere with the boundary layer and create a turbulent airflow which "extends" that boundary layer. As long as the moving air "sticks" to the boundary layer, there will be no separation. The point of VG's is to delay the boundary separation.
In order to maximize the efficiency, the VG's are mounted as far back on the roof line, at the highest point (if possible) to re-direct the airflow separation towards the spoiler.
I dont believe VG's create lift.. just interference drag. As for the "roof vane" there is very very small induced lift (which unloads suspension not the tires). With induced lift comes drag.