To answer the question, a wideband O2 is different than the factory O2 sensor in that it can read voltages which span the entire range of rich to lean. The factory or aftermarket type O2 sensors can only send a very narrow band of voltages to the meter. On the other hand, a temp sensor (EGT) can read all temperatures. The only problem with an egt sensor is that you need to interpret the data. High exhaust temps could be caused by either a lean condition, or fuel igniting in the exhaust path. The ideal tuning tool IMO is a wideband lambda meter (O2).