I just purchased AR3 robot kits and stepperonline motors on Jan 22 and @Chris Annin releases today, Feb 6, the AR4 version. This is a great project and I'll just have to read/study and upgrade the changes which fortunately look minimal (I missed the new electrical kit Chris already prepared now).
Last Thursday I purchased a Creality Ender-3 S1 that finally is giving me great printed pieces. Okay, start the changes ... :)
Thank you very much, Chris and all posters and Youtubers that have shared their builds.