A friend of mine who does a lot of long hauls, has a diverter installed and it does contribute somewhat to better mileage. His trailer hauls race cars, is almost 10' tall and has a flat front. The diverter is a vertical "V" shape that has support brackets in the bed and back of the cab roof. It is not easily affixed or removed and does not look fast or cool like a wing. I don't know if it was purchased or fabricated. His truck is used for little else than that application.

Gard