2004 – 2021 STI. (1990 – 2021 EJ series engines). 2002-2014 WRX. 2002 – 2014 WRX. Manufacturer's Part Number: 551. 2004-2021 STi. • Allows for easy press installation of rear main seal. • Simply turn the 4 bolts in a crisscross pattern to walk the seal into position.