MakerBot Print is our newest print-prepration software, which supports native CAD files and STL assemblies,
allows you to interact with all your printers via the Cloud, and many other exciting new features.
I just tried that stl for the combustion liner, and it did not come out good at all on my Anet A8.
What did work perfectly was to use the original stl and set Supports to Everywhere, and overhang to 80 deg in Cura. That resulted in a perfect support ring for just that section, and nowhere else.