In the mid 1970s if you wanted a BMW with 4 doors, you would have bought an "E12" (the BMW code for the coupes was "E9").  The E12s had very similar mechanicals, sharing not only the drivetrains but also many of the suspension components with their E9 siblings.

To the public the E12 was known as the "5 series," in accordance with BMW's newly rationalized product terminology.  And within the E12 range the 528i was a standout choice ("5" for 5 series, "28" for 2.8 liter motor, "i" for fuel injected).

This car is a very nice example, and has gone to a passionate collector of 5 series cars.