Since I have a 997.1, I have not researched whether the 996 might benefit from the low temperature thermostat. It physically fits. Here's a link to the LNE page for the LTT insert.
By the way, to save $25, I made the insert removal tool out of PVC pipe ground down to the proper shape.
https://lnengineering.com/160f-low-temperature-thermostat-insert-only-use-tool-106-062-to-remove-install.html