Mine never worked right after having him rebuild it, and he didn't believe me. YMMV.
Also any (EJ Subaru) alternator should work as long as it has the 2 pin connector (assuming yours uses the 2-pin connector)
-----Added 11/23/2009 at 09:10:00-----
Also, if you need one RIGHT NOW. Norm's has about a million used ones in stock.
-----Added 11/23/2009 at 09:11:20-----
And further more ... Even without an alternator you can still drive the car. Just charge up the battery and you can go for a long time if you have the headlights off. As I have proved ...