If the donor subie is automatic, don't forget the FOUR 12mm torque
converter bolts under the rubber plug at 11' o'clock if looking from
the front of the car.  They can be a pain to get to, try a 1/4 inch
drive 6 point socket.

Then, once you lift the engine a few inchens to clear the motor
mounts the two should separate without too much trouble.