You can find it here: Outdoor IDEX build
Those have often been discussed and don’t do anything. The limit is the machine itself then. You can already srew the machine up with the motors that are in it if you really want to. You can also achieve insane speeds with the ones we use (look at mine or @stevempotter’s builds/cut speeds). If the steppers skip steps something else is off. I’ve never had them do that.
I am using Estlcam as the PP as well, it works great but needs a USB cable that sometimes fails. 
Besides that it is great to use, has got a touchscreen mode, touchplate support, Controller support, support for Keyboards to control the CNC… So it’s quite nice. 