If anyone if still wondering about tints laws for mass, should go check out this website Tint laws
wow ok, sorry to bump this pretty thread but i came across this page now and as i checked the law info, i have to update this, in case anyone would search for relevant info about tint laws, because that site above is quite out-dated.. hasn´t been updated for years though there have been some changes (e.g. SC limit is more strict now, 27% and not 20%, etc.) so better to check some more up-to-date source, e.g. here
// and enjoy the ride!