I want to replace my 98 EJ22e with a EJ25D plus transmission. What do I need to retrofit?
aside from the motor and transmission you will need the ecu and possibly the wiring harness (if it's n auto you will also need the tcu) I believe the drive spindles have the same spline count and that the drive shaft should be fine as well.
Search Subaru Impreza Questions
Are you a UK consumer? CarGurus now has a discussion forum in the UK.
Subaru Impreza Experts