Competitors to the BMW 5 Series include the Infiniti G, Audi A6, Lexus GS, Mercedes-Benz E-Class, and Cadillac STS.
The 5 Series got its name by being the fifth of the "new series" cars after the V-8 and Isetta era. The preceding models were the 700, the "New Class", the "New Six" 2500/2800/Bavaria and the CS. The 5 Series was intended to replace the older New Six sedans.
The body was styled by Marcello Gandini, based on the Bertone 1970 BMW Garmisch 2002ti Geneva show car. Gandini also did the Fiat 132 and Alfa Romeo Alfetta, two other cars that have a similar design.
There have been five generations of the 5 Series to date. To differentiate between them, they are referred to by their unique chassis numbers (EXX).
The 5 Series began the BMW tradition of being named with a three-digit number. The first digit (5 in this case) represents the model, and the following two digits (usually) represent the size of the engine in decilitres, which is the main distinguishing difference. Additional letters or words may be added to the end of the three-digit number to define the fuel type (petrol or diesel), engine or transmission details, and the body style. The 'i' originally stood for (fuel) 'injection'.