The yare cheap at about $50 on UK ebay

 

Are they really? I can’t seem to find any.

 

In case anyone is still interested in this, the people who actually tuned and performed the electronic portion of this manual conversion did a very detailed, techy/nerdy piece on how you actually piggyback the ECU in this car and tune it.


If phrases like "twisted pair" "CANBUS Gateway" and "packet sniffing" float your boat, you might be into this.

 

IMHO:
The 'disconnect each sensor/actuator one at a time' approach seems implausible, when much more efficient methods are available.
I would think they replicated the approach Dale used, or more likely just downloaded his spreadsheet and ran with it.
Comment on lack of wideband O2 sensors seems strange when the upstream sensors are wideband. Seems more likely to me they did not want to implement the software so went with something they already can support.
I assume gen 1/2/3 ECU comment refer to AJ26, AJ27, and AJ34
Comment on these ECUs not being tunable is not correct, since in theory all that is needed is changes in tables/parameters.
I think that the point is that the OEM Denso ECUs for AJ26 and AJ27 are hard to decipher/reprogram because of multiple factors (Less well supported processor [HC16], dual processor architecture, clunky Flash technology, extended 16 bit addressing, etc.), and the effort versus creating a new ECU implementation with new hardware is probably less effort (also more rewarding if you want to sell that hardware and software). So kudos to them for putting in the effort to make a viable alternative platform.
I think the AJ34 is a different proposition (different processor) and more approachable/supported.