A:Answer Yes, you can absolutely do this. Out of the box, it's an M.2 SATA SSD.
M.2 drives come in two different forms: SATA and PCIe (NVMe). This laptop comes with one SATA drive pre-installed, but it WILL support TWO NVMe drives. I'm currently running two 970 EVOs in this laptop.
It is fairly difficult to upgrade the laptop due to the motherboard being inverted. You'll have to disconnect the battery, speakers, and a handful of ribbon cables, and then remove the motherboard in order to install the new drives. It's not optimal, but it's not especially difficult. Just take your time and be careful handling the ribbon cables. Here's a good walkthrough video if needed: https://www.youtube.com/watch?v=698R4kdSjgk