I had buy this small CNC some time ago due to a good price and that was having ball screws and seems more rigid from the cheapest 3040 model , but came with a small 250w spindle and without endstops.
As you can see in the photos i have upgrade almost all the important parts to add stability and rigidity in Z axis with the bigger (800w water cooled) spindel, and i make some cheap wood enclosure to reduce the sound …works pretty good!
if you are interested for the Y axis spindle bracket here is the LINK