horse wrote:
Please note they are much higher then diffuser itself, and they are not just flat plates with slots.
What i can see, is 3 vertical airfoils on each side, one after another (not the most efficient configuration, but space is limited due to the regulations), bending the flows outwards, towards one of low pressure wakes behind rear tyre.
Added benefit for diffuser would be lower pressure area on the inside facing side of this device, which helps to extract air from diffuser, increasing efficiency.
Multi element turning vane, sort of IMO.