I did these Mods 5 years ago and also did the Grill Cover on My 2010 FEH. Got the idea for wheel covers from ECOModder. I just looked at FFE front end and it isn't smooth like a airplane wing. It has grill relief pieces and center half is recessed, maybe not a big problem, but it isn't...
You missed the point, this is a aerodynamic mod, makes the front of the car smoother, less drag like an airplane wing. Same with the wheels. The improvement is very obvious on the CMAX. If someone lives in the Atlanta area I could put some on and see how it works. :)
Paul
I made Grill Covers and wheel covers for my CMAX that improved MPG's by at least 5 mpg, I don't see why you couldn't do it to the FFE. Here's a Link: http://fordcmaxhybridforum.com/topic/6568-how-to-drive-a-cmax-hybridffh-to-get-great-gas-mileage/page-1 Also we use 50psi with excellent tire...