Called my insurer, Direct Line to ask if getting my rear passenger windows only tinted on my M3 would affect my premium. They said it would add around 5% to my annual premium and £300 to the excess! Needless to say I will not be doing it. My wife called her insurance (admiral) to get tints added to her Mini S electric and they added the mod with no charge! Just for info if you think it will not affect your insurance, check!