The video is from 2013, at which time E-PCIe may have been the interface of the future, but as of today you may have trouble finding computers or interfaces with such a connector. As I understand it, the extension of the PCIe bus out of the computer is Thunderbolt since many years. Alternatively use USB3.
What is the main reason for you to be interested in the MADIface XT ? Is it the three MADI buses? A PCIe card like the HDSPe MADI FX would not be an option for you ?
Note: if you might also need instrument inputs (Hi-Z), the Mic inputs of the MADIface XT can't be switched to Hi-Z, so you'd have to work with a DI box.
If you only need one MADI bus, I would rather recommend you to look for example in the direction of UFX+. This gives you DURec, more analog I/O, two phones outputs, 2xADAT, 2xMIDI, direct USB port for ARC USB, ..
BTW .. in terms of that you didn't find this product in shops:
Thomann can deliver: https://www.thomann.de/de/rme_madiface_xt.htm
Sweetwater can deliver: https://www.sweetwater.com/store/detail … -interface
Newegg can deliver: https://www.newegg.com/p/0SJ-001T-00096 … klink=true
And .. Amazon is not typically a shop for studio devices. Some popular RME devices you will get there, but not all.
BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub14