dell xps 15 -> 144Hz external monitor?

One simple question:

Has anyone succesfully connected the Dell XPS 15 9950 (4k touch, 960m, 16gb ram, 512gb) to an external monitor that runs on 2560x1440 @144Hz?

I have asked Dell employees over chat in three different countries, they all say different things.

I would think that one could use the thunderbolt3 enabled usb-c port to do this by running a usb-c to displayport cable to the monitor.

I have searched the internet for a week and didnt find a conclusive answer. 

The usb-c to displayport cable exists (Plugable and Startech make them) and both are capable of driving an external 2560x1440 monitor @144hz, but it is unknown if Dell's XPS 15 supports this. 

I would love to find out your experiences! If you have experience with other resolutions @144hz, or even @120hz, let me know as well! 

If it's not possible it's a dealbreaker for me.