Hahahaha. Unless you wind tunnel test for the proper placement of the tabs to direct the airflow, you are gaining nothing other than a lighter wallet. This is using the same theory as aircraft use. Vortex Generators. They reduce the vortices that come off of a fixed surface to reduce drag. I don't think there is a single gain since we are only talking 55-75 mph speeds on vehicles. Aircraft benefit from Vortex generators greatly, but we are talking 300+ knots air speeds.