At any rate, this is where my idea of the underbody flow solution originated...
I could be saying 2+2=5 here. But, I do know that most air flow that passes between the front wheels never makes it to the diffuser; instead, it's redirected outward by the bargeboards and creates downforce at the front of the floor. Otherwise, underbody efficiency would be markedly reduced, because anything less than a full-width diffuser is incapable of moving mass flow at the same rate in which it's introduced into the system.
My idea is that the slots "push" outboard the area of mid-floor stagnation such that the scope of the bottleneck is reduced.
