I bought a machine, Debece DTR 200S, in the US that supposedly came from Germany that seems nearly identical construction.
Software that comes with the machine is from Germany also. It is written by a person named Lewetz and called WinPC-NC. While it may be popular in Germany, there is no support in the US and I am changing my controller and CAM Software due to issues that can't be resolved due to language barrier.
Constuction is very good. The Kress motor is a dream. Mine came with limit switches and dust collection system.
There is another posting on CNCzone about a bad business contact with Debece that you should read. But, it seems you are looking at the German site anyway.
Continue your own work.
Stiffen up the sides of your gantry and it will be much better than that Ebay machine.
Your slides are supported full lenght by the aluminum profiles, while their gantry runs on long rods supported only at the ends. OK for a printer, but not for a mill.