Cycle wings on open wheeled cars

[alolympic]

I know it is very difficult to generalise, however....
From an aero perspective, is it better for an open wheeled car to run with or without cycle wings?
I know on a road car that is open wheels, the law dictates suitable covers to minimise water and debris being flung up from the wheels.
I also know that open wheeled cars create far more drag than a similar car with wheels fared in to the body
But....
I still think that most cycle wings fitted on cars will contribute more lift because they trap air that would otherwise be free.
Has anyone had the same car with and without cycle wings and felt any difference?