I got my Vive 2 days ago. I had also to bump my rig even if the older one was a very decent one.
I have now an i7 6700K 4Ghz, 32Gb DDR4 Ram, 1000W, ordered an GTX1080 but didn't receive it yet. For the moment I did the test with the older GPU, AMD R9 290x.
My feedback is that Vive, and probably simply VR in DCS is very hungy. I truly cant use it now with the current GPU which is not bad. I have headaches just by looking around without flying. Looking around in the this job simulator is very smooth.
Without a very good GPU, consider your choices carefully before jumping into VR and probably be ready to invest in a monster rig to really use it in DCS.
Until I receive my GTX 1080, I will use TrackIR, cause now I just cant touch Vive in DCS.
I hope this feedback will help.
edit: I have the config mostly set on rather high. I will test a down tuned config.