This 2.5L shortblock that comes as standard issue in the USDM STi will easily swap into nearly any Subaru with a turbocharged 4 cylinder motor.  It is an excellent choice for any WRX owner looking for an increase in displacement and torque.  In its stock form, this block is capable of reliably supporting 465 crank HP and can be easily built to withstand more power (see our Gruppe-S staged motor packages).  When coupled with the stock WRX heads, more torque and power will be realized but the the true potential of this short block will be unleashed with upgraded cams (such as the Helix) and valvetrain.