Here in the states you are allowed tint on all windows but the windshield. As far as I know, you can't get it done at the "factory", but the dealership will do it for a fee ($400 I think). The dealership does a great job though. I've had my wife's X3 done there as well as my coworker's M3.
2013 BMW 335xi EBII over Coral Red / ///M sport / Premium / Cold Weather / 6MT / Nav / Dynamic Handling / HK audio
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Previous: 2007 328i / AT (boo)
Previous: 2004 325i / MT