Here's the thing about a cop making a traffic stop. He has a gun and there are dozens of cops around the country shot while doing a traffic stop, so the cop is rightly nervous. I want him as calm as can be so I do all I can to not increase any anxiety. I tint my windows legally. I lower the window, put my wallet on the dash and my hands on the top of the wheel. Increases my chances of getting a warning and also keeps me from a bad day with a copy who may have already had a bad day. You can read daily about bad encounters between citizens and cops when a little less anxiety and a lot less lip would have kept a situation safe.
We don't pay our cops (and many others) enough for the value of their work so some less intelligent folks slip through the vetting. Get that guy on a bad day and then make him nervous with your tint and attitude and you are the dumb one as well as the cop.
Remember, the cop does not have to shoot you for you to have a bad day. He can decide between a regular ticket and reckless driving. He can decide you to be arrested and taken in and your car towed. If the appearance of your car is worth more then good luck to you. You will need it one day.