I had a look at the Wiz website. The description of what they do states "disable the closed loop". I took this to mean the lambda sensor circuit?
When I ordered the ECU flash on their website I also ordered two of the blanking caps for the Lambda connectors into the wiring loom.
When I spoke to Dave, aka Grant a few days later, he suggested leaving the Lambda's connected.
He said some people have disconnected them due to still having some on/off fuelling in certain cconditions - perhaps when cat removed.
I have left mine connected and so far all fuelling seems superb - but I've only done 300 miles so far - I will maybe do a test with them disconnrcted in the summer and compare the running and fuel consumption - maybe?
Phone Dave at Wiz and ask him to clarify?
Cheers........Grizzly