I ended up abandoning the MPGuino because this car has a peak-and-hold injector, which isn't supported yet. Here is a thread about that. There is hope... if you want to build a signal conditioning circuit or rewrite the code.
http://ecomodder.com/forum/showthrea...or-6841-4.html
I tapped directly into the injector wire at the plug near the throttle body. I can't say if it was on the + or - lead, because I couldn't distinguish colors on the wires there.
For VSS I tapped into the yellow wire with the red stripe on the harness heading up to the instrument cluster. Check out page 155 of this PDF:
http://jdfinley.com/downloads/Subaru...anualPart2.pdf