I was thinking about this and it is a completely stupid idea but I wondered what people thought:
Obviously the drawing is of this years Red Bull but that's not important right now.
I was wondering if it ('it' being the lowered air intake) would be chosen to lessen the force on the rear tyres due to the moment created by the drag force on the air intake. By lowering the height of the airbox they decrease the length of the lever arm where the force is exerted.
This has the effect of lessening the loss of front downforce at high speed.
And yes, I know, I know there is a whacking big rear wing on it and that the force may be negligible but it is just an idea.