[aerohead]

I'm reluctant to make any general statements.I've seen carmakers do both upper and lower.Chrysler has some fake upper intakes,today's Yukon HYBRID has fake lower driving light openings,and a minimized radiator opening.Dr.Tim Maxwell at Texas Tech told me that on the original Taurus,that air actually came "out" of the upper grille opening.I doubt there's any hard and fast rules.As members have mentioned,proceed with diligence,on the look out for heat-and-serve engine parts.