What did you find to make you think it is a narrowband sensor? I have not found anything completely definitive but the information I have gleaned off of the forums is that it is a wideband sensor. If it's not, I may have an easier time working around the issue.
I saw that site this morning, and even considered buying one just on the off chance that it is compatible, but you must buy 10 minimum of the item.
Also, the picture shows a one wire O2 sensor, and with all of the compatible vehicles and o2 sensors that it shows, I don't believe they are really the same sensor.
From all of the research that I have been doing it looks like this is supposed to be a wideband sensor. I'm not sure what the voltage readings are supposed to be but mine started at about .5 volts and went up to and stayed about 1.2 after the vehicle warmed up. There was no change when I opened up a vacuum line and caused the engine to slow (or even stop as I removed a large vacuum line). It also rattles when out of the vehicle and is shaken.