Going VR requires your game to generate two screens from two different aspects. This is almost like running DCS twice at the same time. Your first priority is the GTX. Go for the fastest you can pay for. I don't think the 970 can qualify to run VR. Next: Memory. Finally, the CPU. DCS is extremely CPU intensive. Nevertheless, for VR, the graphics card is the most critical. Do not get two cards. SLI is dead for DCS.
There are tests you can run to see if your rig can support VR. I get pretty good frame rates using just a 1060 and Trackir but my rig fails the Oculus system test.
Also, keep in mind that VR will be more prone to promoting Motion Sickness compared to Trackir type head tracking devices. I'm sure there are electronics stores in your area that have VR demos of low-res games. Spend at least 4 or 5 minutes immersed to see if you are susceptible to this health issue.
P9x79 Deluxe, Intel i7 3820, 4.6 GHz stable, Corsair H80 hydro cooler, G-Skill 32GB DDR3-2133, GeForce GTX 1060 8GB, Kingston 120GB SSD, Crucial 256GB SSD, CoolMaster 1.2kW PSU, Samsung 27", Samsung 4K, APC 1200 UPS, Logitech G-15, G-13, G27, Saitek Pro Flight Rudder Pedals, Thrustmaster HOTAS Warthog, Logitech Z5500, TrackIR 4, (1TB, 2TB, 3TB and 2x 4TB) ext HD