If i remember correctly a cop pulled me over becouse of my blower sticking up to high. He said if i can't see my radcap from the drivers seat then it was illegal. His reasoning was that if my car was overheating i would'nt be able to tell. I showed him my various collection of gauges, but he did'nt seem to care. Dosent sound like a law to me. FYI bumpers on trucks are optional, so they are not required to be street legal.