Well done, you found something re: ducts (f-duct)!
Unfortunately that is not a circumstance of straight-forward drag reduction; it is a special racing circumstance of desiring to control the downforce and drag characteristics of a wing via skirting the rules that state one cannot have moveable wing elements. While they welcome drag reduction whenever they can get it, their main goal is downforce production. I don't see it being applicable to the street unless your street machine is designed for illegal speeds and sports a wing.
You could do an Ecomodder search for "duct" and find 124 hits to dig through...