The Monza was planned as a successor for the Commodore Coupé. In the late 1970s the Commodore C model was made as a two-door version (as was the Rekord E1), but still as a sedan type car. The first model of the Commodore the "A" series had a regular coupé in the production line and Opel desired to make a newer version of their large luxury coupé. Work began in 1976 and in 1978 the first Monzas were available to buy. The cars to compete with would be the Mercedes-Benz C123 and later the Mercedes-Benz C124 and the BMW 6 Series (E24) models (coupe models), and any other large luxury coupe. But what Opel hadn't realized was that the old ways were too old. The car was big without being hugely luxurious. This did not mean that the Monza was not comfortable. There was plenty of space inside the car, and the enormous seats left you with a feeling of sitting in a much more upmarket brand than Opel.