Does anyone know what the maximum tint % you can have on our cars in Missouri? I recall a few years ago you couldn't do the front driver/passenger side windows at all, but I believe that's changed. I've heard horror stories in the past (could be urban legend) where cops would pull people over for their windows being too dark and taking a key and scratching it off. I'm sure it's not 100% true, but I'd like to avoid a ticket if possible.

If you call a tint shop, they will be able to tell you.

It shouldn't matter what state you're located in. Like here in Florida they knew that Washington state's max was 35%. Also, you might be able to google it. I found it for Wa state, but didn't look for others.

Found this:
http://www.solargard.com/Assets/PDFs/Technical_Docs/State_Tinting_Laws.pdf

Should help everyone who's curious.

Here are the specifics:
35 on side windows
No mention of front/rear windshield
http://www.moga.state.mo.us/statutes/C300-399/3070000173.HTM

In the past, I do know cops that would give people the option of peeling off the tint or getting a ticket.

Front windshield- a lot of shops will not do so but some will. The other option is to just get thr brow done.
Front windows- 35%
Rear windows and rear windshield- Any.

Also, for them to determine that your tint is too dark they must have a tester...

I have 20% front (including brow) and 12% rear. Never been bothered about it..

Kinda funny story about the anything goes on the back...I used to know a guy that painted the back 3 black, from the inside...and it was legal.