[ScottyS]

If you replace it with a recycled tranny (not from the same year-model), you'll have the same issues I ran into on the tranny swap - clutch type, final drive ratio, and speedo sensor.

The final drive is the primary determinant, make sure and get the same as your existing rear end, or else you have to swap that too.

You also need to get the same clutch type as your existing setup, to avoid buying new clutch parts, switching to cable or getting a different slave cylinder, etc.

The speedo sensors switched to electronic at some point, but from what I hear you can thread in the sensor from your old tranny to the donor one.

I think WRX tranny replacements are a fairly common occurrence given most drivers' habits, so check on NASIOC or whatever to see what is the most common fix-it path.