What is the street legal law for Illinois?

Well i kno for a fact that street glow can not be used while driving but if you are parked it is ok... 5" exhaust is also illegal... Anything that is proven to be over 545 bhp is considered to be illegal but it is really hard to control that so its cool. Basically dont go over board on your car. If you have to ask if its illegal just dont do it.