I had all five windows tinted in my Z and never had a problem.
I recently took out the tint from passenger and driver windows.
Not really sure but i think i have smoked windows , They look tinted after i took the film off, I also cleaned them.
Here is something i think is funny, I drive a ford festiva.
I took it to the tint shop to tint all five windows.
Three hours later i was on the right side of 101 .
I got tickets for tinted passenger and driver windows and the reason he stop me was cause my sticker(month) was faded from the sun, I also had a cracked windshield.
All i paid was $80 for the tint, Still have my tint on though.
It's been over a year without a problem.