The heat sink of the MP600 can be removed relatively easily (with a fingernail, no tools necessary), the SSD can then be mounted under the heat sink of the mainboard. It worked without any problems with this mainboard and MP600. However, I cannot say whether the cooling performance is better or worse.

This mainboard has 2x M.2 PCI Express version 4, can I still use an M.2 SSD PCI Express 3 or do I have to install a 4.0?

I am planning to remove the SSD heatsinker and use the MOBO one. According to this the heatsinker is removable:
https://www.guru3d.com/articles-p...

Google rather shows user reports that point to an incompatibility. Have you physically tried whether it really works?

see incl. pictures: http://forum.corsair.com/forums...
and on the removability of the cooler: https://www.reddit.com/r...

I would also be very interested to know if the SSD really fits on the board. Or, if you order this and it doesn't fit, I assume that you can return the SSD?

The heat sink can be easily removed as an option for the MP600. The mainboard is cooled with a cooler, so I think so, but that's exactly what I'm thinking about too:) If we would finally get!! our package would give exactly answer.:D

According to our own research, this should fit. For this reason, we have listed this SSD in the accessories.