all you need is an Adjustable Fuel Pressure Regulator, and an AFC. also, adjusting IDLE fuel ratio is pointless. the ECU will just 'overwrite' what ever settings you give it. The ECU reads O2 and adjusts accordingling. Leaning it out to death will only mean a blown motor IF your O2 sensor ever fails. I'd rethink your position on fuel management.
I'm not saying a standalone system is NOT a good answer. But 95% of your motor harness/Ecu is working properly. Swapping all that out and starting from scratch is worthy of 90 midol nights.