This is a flexible/universal mount that fits directly onto the stock stepper motor mounts. It is held in place by the top 2 stepper motor screws - the mounting face is 5mm thick, so you will need m3 bolts that are 5mm longer than the ones you currently use.
The top surface has 3x M5 holes that are spaced 10mm apart - these can be used for attaching additional mounts or aluminium angle to run your drag chain on.
The front and side faces have extra M3 holes for adding any other accessories you might want, or for securing cables with a cable tie (see photos). The front face also has an extra set of slots for a cable tie - I put this in as a 'might be useful' one day, there is no intended use as it stands.
I used PLA - just use whatever the rest of your machine is made from.