Upgrading the SSD, will it be compatible?

Yes. I just completed this exact upgrade just minutes ago. I got an external M2SATA to SATA adapter/enclosure at the same time I bought the new SSD (http://amazon.com/gp/product/B00SM0M5QC?... - enclosure instructions were horrible). I put the new SSD in the adapter and connected it to one of the laptop USB ports using a SATA to USB adapter I already had (http://www.microcenter.com/product/35793...). I wanted to retain the GPT partitioning with the support partitions and found the Samsung Data Migration software inadequate to do this (at least one partition was not recognized). I also looked at EaseUS ToDo, which also did not appear to have the needed capabilities. MiniTools Partition Wizard Free Edition (http://www.majorgeeks.com/files/details/...) performed the migration well. I did a disk clone keeping all partition sizes the same, moving the last, ~7GB, partition to the end of the new drive and then resizing the C:\ drive to consume all of the new space. The clone process took ~1 hour, with a reboot needed to clone the boot partition; I ended up with a 457 GB C:\ drive.

"The XPS 9343/9350/9360 has one of the best SSD slots I had seen ever. It does not matter if it is PCIe/NVMe/SATA. They all run very fast. As long as it fit, the computer can recognize it and you can put whatever you want on it.

___Formatting and initializing the drive can go as easy as Windows Disk Manager, or DISKPART for more advanced users.

Macrium Reflect is very powerful if you want to clone sectors."