Omega,

Here in Texas the only windows that have to be legal limit are any windows from the drivers area forward. Meaning the front door windows have to be legal limit, and anything else can be blacked out if you so desire. I am assuming that is the same everywhere as Kansas, and Missouri are the same also. I would at least put 5-10% on the back window just to relieve the stress of headlights in your mirror. You will never have to readjust your mirror again!!!

I have absolutely no problems seeing through the 5% at night!!! Especially with all the lights around here in DFW. Where's dem dadgome stars at????

Good luck!!!