The typ 300 line-up was revamped in 1957 with the introduction of a new platform dubbed the W189 as well as major styling and internal modifications.
Updates included bodywork lacking the B-pillar for a sporty hard-top look and a slight price increase for all new vehicles. Having had a production time of 5 years, all models produced throughout 1962 are very rare today, especially the Cabriolet D which was built in only 65 units. At the opposite end, 3,077 saloons were sold with an updated engine that had received a higher compression ratio (roughly 8.5:1) and a new Bosch fuel injection system leading to an increased power output of 158 hp.