A L8 cossie ecu has a standard lambda sensor fitted, if i fit a wideband is it just a case of ditching the lambda or can i connect the wideband controller to the ecu?

its a techedge j2 setup ive got

 

If your wideband controller has a narrow band emulator output then you can feed this to the ECU. If not, a wideband won't give the correct signal to the ECU so it will need to keep its own narrow band sensor. The two types of sensor work in completely different ways so are not cross compatible.