on a subaru there is no need for a press, there is a pinch bolt on the knuckle that holds the ball joint in. SOAK the shit out of it, if you dont have a torch to heat it up, that bolt has a tendency to break. since you’re replacing the ball joint anyway a pickle fork is fine, the damage ive usually seen is a torn boot so the old one doesnt matter or like newman said a nice blow to the lower control arm should break it free. Once the pinch bolt is out and the knuckle is removed from teh lower control arm it may take some wiggling and what not but the ball joint should come out without a problem, new one goes in along with the bolt, drop it into the lower control arm into the knuckle and viola replaced.