I am not having any luck figuring out where to get extra pins. I will look at my factory wiring when I get home this weekend, but I doubt that Subaru would have included pins and wiring that don't go to anything.
I found the resistance values for the 2008 Impreza on MP3car
http://www.mp3car.com/car-audio/1209...preza-wrx.html
I don't know if that's the same for our car, but I think that might be a decent starting point to start figuring it out, unless someone can get their hands on a 2012+ Impreza or Forester SWC module and measure the values the Fujitsu Ten is expecting.