What do you guys think about using Boundary Layer Suction to reduce drag?
BLS uses pump to literally suck the drag-creating boundary layer:
Boundary layer suction - Wikipedia, the free encyclopedia
What would be the optimal place(s) to place the inlet holes?
Remember that most cars have a huge angles when transitioning from grill to hood to windshield to roof.
So I think the inlet holes would be better placed in over the hood and the roof and in the bellypan. Maybe also on the doors or fenders.
The vacuum pump may be wired so it turns on at certain speeds reducing its power consumption during stop and go traffic.
One patent addressed its use in the underbody:
Patent US20080252099 - Boundary Layer Suction System For A Vehicle - Google Patents