I just changed my O2 sensor today. When I was removing the old one, I realised the previous owner must have changed it b4, cos it had 2 white wires & 1 black wire, & was the Bosch brand.
Upon removal, the O2 sensor looked really crapped. Replaced it with the new EL O2 sensor, which happened to have 2 white wires & 1 black too. I have resetted the ECU... let's hope the fuel economy gets better!