How many wires is your stock o2 sensor?
You could easily cut the loom and tap your wide band into it BUT in saying that, the stock sensor usually uses 1 or 2 wires. Widebands use 3 or 4.
I'd rather get a new boss welded after the sump and run the innovate loom to it. They are a bulky unit and need to be mounted quite close to the sensor.
That way you still have your stock o2 sensor / wires and the wideband in your exhaust.
Can the wideband be interfaced with the ECU at all?
Or is it simply a gauge for you to monitor yourself?