I live in California, it's a stupid law, but I have my fronts tinted 50%, which inst that much, I wanted 35%, but the tint shop I'd be in there within a week with a ticket. Basically any good tint shop can you get you hooked up with good tint, with life time warranty that matches. Hard part is avoiding stupid laws and tickets.
I wanted tinted front windows, basically, to keep people from looking inside my explorer and seeing a $1500 TV/DVD stereo system. My car was broken into once already.
Stupid law, you'll never see a Mercedes or BMW or luxury car tinted LIMO black pulled over. Lets face, you drive in LA or Beverly Hills, every movie star, sports athlete, or music artist has their Benz tinted like 10% black, so they cant be spotted. Its a great security, privacy, tool. Just my
2cents.