For the IIc our stage 1 wideband controller is the best fir out there. Our controller uses a 'standard' Bosch LSU 4.2 wideband sensor (same sensor Audi, VW, AEM, Innovate, etc. used), ties directly into the ECU via the CAN bus, has 2 additional programmable 0-5v outputs if you want to drive a gauge and/or seperate logger.