A simple minded individual who has let a badge get to their head. BMW Douches often believe they drive the best car in the world, and that everybody hates them because they cannot afford one. This ignorance affects their driving skills as well; cutting people off, not using a signal light, tailgating, etc. To a BMW Douche, everyone that doesn't drive a BMW is a "hater", and simply hasn't experienced the "ultimate driving machine". They often purchase the bottom of the line 3 series, then consider themselves a true BMW fanatic, better than everyone else on the road. BMW Douches are becoming more common nowadays with low lease rates and abundance of available credit.
For examples of BMW Douche, type in "BMW" in Urban Dictionary.