What I don't get is why folks haven't removed those brake duct vent covers like I have - the big ones to each side of the center opening? My son and I took the entire backing piece off that has the inside lip trim for the center opening, plus the outside (big holes) atached - I cut off the outside hole covers, retaining the center inside trim - looked ugly without it - all three holes are now wide open, and I'll probably cover all three with aluminum mesh.
You can never have enough air coming into the radiator, lower engine, and brake areas...