Heres the scoop. It's an ION, resale isnt that great but best in it's class of sub $16K cars. A true PPG professional (expensive) paint job won't hurt it. Many cars are sometimes damaged during transport or while on the lot at dealerships and must be retouched, you would never know as the job is done professionally.
How to tell? overspray is the #1 culprit, especially roughness under the hood edges. Ripling and uneven colours are a dead giveaway too so choose your paint shop carefully and make sure they understand you want a professional job.
Polymer paints just as well as metal if prepared properly. Will it hurt your value? not really on this car, unless you are looking at rading it in, dealers will use that against you. If it is professionally done its your business ;-) Private sales are unafffected again, if professionally done. If you plan on keeping your ION, paint it to your liking and enjoy driving your unique car!