Sorry, assumed that you had a copy of the Mazdaspeed manuals from
https://drive.google.com/drive/folders/0B3YbfB30DxW0bEdwS0xSNGVXMzAThose diagrams are in the wiring_all.pdf file.
If you haven't already done so, you should save all these .pdf files to a local HD in case that site goes AWOL.
Regarding the gauge and sensor box, V2 is imminent, I'm waiting on the new PCBs.
* Same small box size
* External buck converter (12V->5V) replaced with an an internal 6-26V->5V converter so you can just wire it up to a fused 12V source
* External serial->TTL converter (for WBO2) no longer required (new internal MAX232 chip handles that)
* Simpler socket (previous dedicated socket really needed ALL pins to be wired rather than adding the required ones initially then additional ones later)
While I'm waiting for it, I'm looking at a sensor box mounting solution near the cluster which will eliminate any issues with the I2C interface to the gauges due to the wires being too long. This will also mean shorter IAT, Oil Temp and Oil Pressure wiring from the engine bay since you wont have to route them behind the centre console to the passenger side.
This is one of the reasons I bought a complete spare NB console, I can get a good look at it from the inside too to figure out what's possible, it needs to be secure, out of the way and accessible.