It's called probable cause...if the cops have reason to believe you may have something to hide, or something illegal, for instance, if they smell weed, they can ask to search your car. You can refuse, but, they can, and usually will call in a warrent, it takes just minutes over the radio. So, they get a real warrent, and then they have the legal right to search as much as they want. So...unless you can tell them they can't search your car, and convince them you don't have anything to hide at the same time...they can check it all anyway. And, for the record, technically, any mod, or part that isn't DOT approved can get you a ticket. I bought an intake (K&N) for my Chevy Trailblazer, and in very small print, on the back...it says not for street use...for race, and offroad use only.