There's a few more pics of the setup above in this thread:
http://www.ft86club.com/forums/showthread.php?t=33486
You can get some info on the 3x data busses used by the 86 ECU from techinfo.toyota.com and there's plenty of info out there around the stock H6 ECU. IMO the electrical side of things is the most difficult part of a H6 swap into the 86, all the custom fabrication required to make it work mechanically is relatively easy.
There's nothing hard about making new headers, tailshaft, cooling system, shift linkage etc etc.