MRT emailed me an installation guide for a different FCD, which they said should work fine for this installation. I've posted it here:
http://docs.google.com/Doc?id=d532khn_11ddxw9gf9
The problem is, it's for installation in a WRX... which differs slightly. So I referenced my Haynes manual, and found that the MAP connector in the engine bay is a 3-pin connector in a sort of triangle shape.

You can see someone had already tried to use these wires for something.... Pin #3 (bottom) is the signal wire, according to Haynes. I'm assuming this is where I'll intercept the signal from. That's not the issue.
My issue is that the installation guide says the FCD requires a 12v power source. The Haynes manual says the reference line for the MAP is 5v. So... is there a 12v line somewhere near the MAP that I can tap to power the FCD?
Lastly, if you notice anything wrong with my logic... let me know. I really wish the people who were doing electrical work on this car hadn't spliced in so close to the connectors.
Thanks.