Originally Posted by spazmoo
My friend has an 04 WRX. He asked me today to do some research on the EJ20G. He said he heard that it was stronger than his old engine. Do you think I should tell him to just get an STi engine?
He could only use the shortblock, and even at that his compression ratio will not be ideal. The piston crowns and head gasket thickness have changed through the years.
In your friends case, I would look for an EJ257/EJ255 shortblock and an open source tune after installation.
If he really wants (or already has) an EJ20G, rebuilding the EJ20G with USDM WRX spec pistons (forged or not) would make an good motor, but not neccisarily any better than using an actual USDM WRX block.