4-GPU success with Cubix + Aki Node + MSI GT80S Dual 980
1080ti can have most on Alienware laptops with alienware gpu apmplifier as that one uses propitiatory connection that is direct PCIE to the cpu, while thunderbolt is 99% like this
CPU-PCIE-PCH-PCIE-Thunderbolt CHIP- TB cable - TB chip- GPU, and not only that is slower but it also brings in latency as those chips are not realtime. so if your main goal is gaming, then you will feel some input lag, and you will have lower fps, as gpu cant use all x4 lanes, because storage and other chips also use PCH chip to communicate with CPU, so you're down to x2 or x3 at best in practise with thunderbolt.
also this video shows in practise how eaven alienware x4 weak compared to full flag pc