ROG XG Station requires thunderbolt 3 connection. Since GL55X do not have thunderbolt 3, they are not compatible.
I think, ROG XG Station does not worth it: as I know TB3 connects to processor via 4 lanes of PCIe 3.0 (for example,
this or
this). Discrete graphics in entery-level gaming notebook does it via normal 16 lanes of PCIe 3.0. So you have only a quarter of channel width.
What we see on
this page: "Rise of The Tomb Raider™ Testing Average FPS 38.0". As you
can see, 38 FPS on ultra is level of gtx 1050TI laptop. FPS is not the only thing to be considered, you may, for example, also need constant frametime for smooth experience, but let not take it into account. Also, with GTX1080 doom goes
70 fps, same as for gtx 1050TI.
GL553VE with 1050TI costs ~1200$, TB3-equipped laptop+ROG XG station+Gtx 1080 = 1000$ + 500$ + 600$=2100$, so, twice of laptop. With same FPS.
