I cannot recall where I saw but I think the Lambda sensors supplied are NTK L2H2. Are there any linearization/characterisitic differences with L1H1 sensor? I am just curious about future sensor replacement especially because of all the leaded fuel being used.

The Sensors are L2H2 NTK Sensors which are off the shelf available, You can use the L1H1 no problem but these are alot more money. Best to stick with the L2H2 which are cheaper and just as good. NTK sensors are very good with leaded fuels compared to the Bosch range and another reason why we use them