I used to have a 2005 mazda3 hatch. I got it tinted to 20% almost exactly a year ago, and then sold it to get my MSP in April. doh!
I also managed to get pulled over for illegal tint and no front plate... (though the cop told me if it was one or the other, he wouldn't have bothered me) so I ended up paying $300 and some change to enjoy my tint for about 4 months.