Tinted windows on bmw GC is £300 plus vat. Private after market tints £200, good quality not cheap. I have asked the dealer to meet halfway. If not, no hesitation on having after market. I see no problem unless you make it one, have done a few sensible mods on my previous cars. Upgraded led lights ect, added extra enhancements to speaker grills and dash, not heard a peep. You would have to be really on the ball to notice.