I was just looking around this site and saw how many mods block airflow to the engine bay. The hotter the engine runs, the lower rpms, .. and the lower rpms, the less distance for the gas your consuming. So I was thinking of a system where you get your aerodynamics with no drag. I was thinking about testing it on my focus when i get my new front bumper.
Diagram 1
Diamgram 2
NOTE: You can still block up the grill if you want too, this project is done below the grill between your foglights.
This is what inspired me and gave me an idea for the duct.
Please dont flame :P