1. The Chromebox has 16gb of internal storage. I'm fairly certain it's using the same SSD model the Cr-48s and other Chromebooks used, which is not easily replaceable (difficult to find a fitting card)
2. Chrome laptops and (now) desktops use verified boot, you won't be able to install your own OS unless you literally crack open the case (there are physical implements to prevent firmware flashing) and flash your own BIOS.
2. Chrome laptops and (now) desktops use verified boot, you won't be able to install your own OS unless you literally crack open the case (there are physical implements to prevent firmware flashing) and flash your own BIOS.