The Cosworth head 16V was first introduced in Europe in 1983 when it not only set endurance records, but also won the Sedan Racing Series in Germany (Senna's first championship). Production for export vehicles was '84-'88 for the 2.3-16. Later, when MB really wanted to chase after BMW, they upped the displacement to the max allowed under the rules to 2.5, but only the Europeans got those.