BMW is a german automaker. They craft their automobiles with precision and quality. Their cars come in many different levels, but to list the most common ones there is the 2,3,4,5, and 7 series. Bmw also offers different engine sizes with each series, so generally a 28 is less power and a 35 is more power. The code for each body/engine type is the level followed by the engine type. a 428 would be a 4 series with the slower engine. A 535 would be a 5 series with a big engine. Generally the higher the level goes the more luxurious the car gets.