If you want to see a saga of a guy dealing with a cop who wasn't familiar with the law
If you don't want to go through the whole thing, just watch the 2 minute video in the first post to see a moronic officer who has no idea what he's talking about. Feel bad for the guy, it's now been 5 months, and he still hasn't been able to get his car back on the road.
tl;dr summary: Cop pulls a guy over in a bone stock Elantra N for having the exhaust in Sport mode. Suspends his registration, sends him to get it inspected. Inspection station tests his car "wrong". By the books, it should be tested in the default mode when you start the car, they tested it in Sport mode. It fails, and can't be re-tested until he provides proof it is fixed. Goes to Hyundai, they can't give him any "proof" that is sufficient, since there is nothing to fix, the car is stock. Registration stays suspended. Hired a lawyer, court date next month.