I just bought a new GS300 and I have an appointment to have the windows tinted next week. I have had my automobile windows tinted since 1981 even though it is against the law in the state of California. The fix-it ticket is $15 and the odds of getting pulled over and written up out weight the sun damage prevention in my opinion. In all of the years I have had my tint, I've only been written up 3 times. Not bad odds I'd say. I never tinted the driver and pax side windows darker than the lightest tint available, but the back windows have always been medium to dark. I think that's the key, not to go too dark on the driver's and pax side. Also, if you see a police car, roll the windows down :D
Good luck