The wheel looks like it might be plasti dipped in this pic? Attachment 18400 I wouldn't sweat it. Scuff and touch up then flog those wheels or keep em. Personally, I'd get rid of them and go with stock size tires and wheels for max economy. I bought mine to get excellent fuel mileage, if I only got 30mpg in the Mirage I'd buy something else nicer that get the same. But you have more hills than I do, my commute is pretty much flat so that is one big factor.
The wheel definitely looks like it was coated in something cheap as it's starting to buckle and peel on all of them I'm going to do a highway trip in a few days to get a better mpg reading.