*IF* we are going to "roll our own" with an unlocked ECM.
I recommend moving to THE standard controller -->
http://www.microsquirt.info/
There is a whole community already built up around this system, from the days of B&G's Mega-squirt D-I-Y project.
It's interesting, but from my reading about it, it requires the removal of all the sensors off of the UCE engine, and using a new set of Microsquirt-compatible sensors. Not a trivial matter if the UCE is not using GM sensors. And I suspect it is not using GM sensors.
If I had to do it without any other alternative, that's one thing.
But if I can leave all the factory sensors and wiring intact, and swap in a new controller that will just plug right in and be programmable by PC, I'd prefer that.
And I suspect consumers would prefer that too.
Also, the Megasquirt controller is not any less expensive, and any sensor changes would add to the price too. And we'd have to program maps from scratch.
I'm not ruling the MS out, but I want to pursue this RD avenue to see if it's as feasible and low-cost as it appears to be.
My aims are for best overall performance with most reasonable cost and easiest installation.