Just found this thread and enjoyed reading it. I've been following Tim's build in FB pretty closely, but I'm planning to install the AM13 on my Sonex B.
Regarding sensors and EMS displays, I was chatting with Mark K while I was at SnF about engine monitoring options and the Microsquirt data standard. He sent me the documentation on it and between that and other online info, I learned a ton about CAN message data formats (there are several).
That led me to a super cool set of open source projects called MakerPlane (makerplane.org) . At this point I feel very confident that it wouldn't be terribly difficult to use an Arduino (or similar microcontroller) to build a MicroSquirt to CAN-FiX bridge to collect Aeromomentum engine data, convert it, and display it on the MakerPlane EFIS (CAN-FiX being the MakerPlane CAN standard).
Here's a YouTube video I did that demonstrates my simple test implementation:
https://youtu.be/hilpmA7j6PgI've continued to play around with it over the last couple of weeks and have had quite a bit of success integrating more and more mock data as well. Obviously, that data will eventually come from either the Aeromomentum MicroSquirt ECU or separately installed sensors. I'm not sure what all sensors are installed on a new AM engine, so it'll be some combination of both.
Anyway, I'm still looking into building an ADAHRS board for flight data, but building my own EMS doesn't appear to be very difficult and it's likely what I'll be doing for my build.