how much to replace two O2 sensors, 200BMW535i

Greetings, There isn't enough information to provide an estimate for you. We would need to have you bring in the vehicle for us to diagnose it to determine which of the four oxygen sensors are bad if that is even what is wrong with the car. My suggestion is to set up an appointment so we can run some test to determine the failure and once we've done this we will be able to provide an estimate for you. Kind regards, Stephane Grabina BMW Excluservice Rockville, MD 20852 www.bmwexcluservice.com (301)231 5400 ext.1 stephane@bmwexcluservice.com