The horizontally opposed and turbocharged 4 cylinder flagship engine of Subaru cars. It has been used in Legacy and Impreza models, and is known for its small size and massive power output in turbo form.
Versions of it are used in international rally racing Subaru Impreza WRC models.
It was used in all WRX models until the larger EJ25 was introduced for the 2003 WRX STi in North America and in 2006 when the Subaru line was revised and the 2.5 replaced all turbo Subaru engines in North America.
That EJ20 WRX just rolled your Vette in a dubie and smoked it!