I wouldn't blame IL too much for that. Seems blue lights would be illegal in pretty much every state. the best explanation i found in another forum:
"The DOT rules, specifically FMVSS (Federal Motor Vehicle Safety Standards) cover what is and isn't legal for motor vehicles, and they are QUITE extensive. As noted by the posters above, pretty well every color but white(Headlamps, fog lamps and back up lights), red (Brake lights and rear turn signals) and amber(Turn signals and running/marker lamps) is illegal. They are so strict about this that the FMVSS includes specifics about what color EXACTLY amber is. It's not yellow and it is not orange, to make a point, as both those colors are illegal for exterior display on a vehicle."
here's the specific code if you'd like to check for yourself:
http://www.gpo.gov/fdsys/pkg/CFR-201...sec571-108.pdf
I will say there is some advantage to living in IL. I grew up in PA and while you don't need a front plate, you have to get your car inspected plus an emissions inspection annually. that means all of your illegal tint and exhaust modifications would have to be removed and reinstalled annually (unless you "know somebody"). MD, where I recently moved from) only requires a single vehicle inspection the first time you register in the state, but requires an emissions inspection every other year, so again, muffler delete or catless straight pipes could be an issue. I do know that in Illinois, only certain counties require emissions (not Champaign, yay!) and there is no inspection, so my 20% tint wasn't an issue when I moved here and we don't have to have those ugle inspection stickers on our windshields. Yeah, a lot of it is annoying, but there are certainly benefits as well!