i don't know what the law is in Mass, but in california any tint on the driver and passenger windows is illegal. I tinted mine 5 % and didn't get pulled over until a year after i did it. All you have to do is pay a ten dollar fix it ticket, take the tint off and show proof to a cop, and your cleared. Its worth it to tint them, because it looks way better and keeps the heat out of your car. My buddy gets pulled over all the time and he just keeps re doing it. So if you dont care about the money thats an option, too.