20% on my Volvo here in Tennessee. I run eastern states and have never had a problem. I haven't been to NJ much but it's mostly because the rates suck, not because I'm worried about my tint. I see all sorts of trucks with tint and watched them for awhile before I decided to do mine. Been that way for 50k/6 months and haven't been pulled in once. Of course if I do get pulled in I have the sense to roll down the windows.
I’d like to do mine to keep the heat down, but I guarantee Idaho would ticket me for it. I was stopped twice in the same weekend for the tint on our personal vehicle while traveling through Idaho to get checked. It was legal both times...
I live in northern Idaho I have 5% on all except my windshield and never once had a cop say a thing even being pulled over for other things
I was by Idaho Falls where the cops are always staked out looking for customers. Being from out of state probably doesn’t help.
Update from my post above. 1.5 years now and I have been pulled over once, in KY. Officer let me go and said I ought to get a doctor's note for light sensitivity. I did. It was easier than I thought. I haven't been pulled over or in yet but I have the note in my truck ready to use.