Rednaxela Xilef :
I want to now, should I get another 980ti FTW (making 2) or get the 1080ti (I will be running Vive, 4k, and high end games)
Well sir, that all depends on how well the driver's scale going forward.
At 4k you should have higher performance with 2 980ti's, but that's not guaranteed.
In fact, the driver's may lead to lower performance, as they tend to be with SLI and Crossfire configurations.
The 1080i will be the much more stable and supported card going forward.