The last time I spoke with the LPP rep about where to place my sensors, he said to make sure it was at least flush with the license plate. At the time, I only had one head unit and was thinking of putting it just below the plate. But now I have dual heads and will be placing them in the grill area in the upper left and right corners.
I have a 2006 350Z but this would apply to any car.
Anyway, this got me thinking. If the head units have full view of the road ahead, does it matter if they are not the most forward surface on the car that a laser will strike first? In my case, they would be almost flush with the grill area of the car but maybe a half inch or so "behind" the license plate surface, which is the leading edge surface of the vehicle.
Let me know if what I'm asking is not clear.