the only prob with prepainted parts is getting the paint to match. it may be the same paint code, but the paint on your body has probably faded a little bit over the years and may not match the bumper.
like the guy above said, have a paint shop match it and go from there.

as for aftermarket bumpers, they rarely fit good, need to have holes drilled out, need to be sanded, fitted, etc. just a large pain in the ass.

with an oem bumper, you can throw it on and you know it will fit and you have the hardware to make it work, etc. just my .02
oh, stay AWAY from fiberglass, 9/10 it is never worth it.
Tony, (running925) used to rock body kits, and he is finally going back to OEM stuff after a few different front bumpers getting beaten and destroyed.
remember, you live in illinois, not florida/Carolinas/etc., i am sure you have shit roads around there just liek us, and body kits hate rough roads