even if the unit is proven reliable, the other thing to think about is what if the ground goes bad or a power wire comes loose? or a fuel supply line starts to leak
if you only have one ecu, and it controls everything itself, if you should happen to have a problem like mentioned above, the car will just die completely, instead of going lean and scattering
keeping it simple is the best way to go, emanage or aem or both proven choices, megasquirt works great but requires sensor swaps and alot of programming
yes even if it was reliable, i have seen people that use the SDS EIC system it adds an extra 2 extra injectors and has little knob you turn to richen it or make it leaner. its better than just adding injectors but i still would not do that cause it makes me nervous just relying on 2 extra injectors to keep my engine from blowing.