Illinois is one of the dieing breed of states to require a front plate also. I was stopped several years ago for no front plate on my
Impala SS. The officer knew it was illegal but she couldn't find the code to write the ticket. After radioing her boss and asking him (He didn't know either) she finally (after about a half an hour) told me to go on my way (no ticket). I have several friends on the local force and they too do not have any idea why Illinois still demands a front plate. You can't see them at night and the officers have to get right up behind you to read the rear plate to call it in.
But you have to remember that Illinois is all about the MONEY (Past Governor is waiting and the Governor before him is in a Fed Jail) and maybe someone is getting paid off to make sure we still have them. Who knows...........
So I don't run them on my X-Runner or my Z. But I do run them on the Wife's 300C (See has the grand-kids an awful lot).