most of the time they wont bother you for it unless you are an asshole to them or give them a reason to not like you. you probably shouldnt go any darker then limo just because thats really dark (on passenger windows) doesnt matter on the back one. i had like as dark as the government vehicle's, forgot how dark like 2% or something and never really got bothered but dont go that dark at night you can hardly see out of them.