The Windows Mixed Reality is a good option if you're on a budget. Some have reported using very high sttings with better performance. That being said, I would definately get me the best computer I could.
If the budget is tight though I certainly would get a top end I5 8600 and a K version if I could. The K versions of Intel processors will have a bit higher clock speed and can be easily overclocked with decent cooling for a bit more performance. With 6 cores, the new I5 processors are quite good and budget friendly when compared to the I7. The I7-8700k is about the best all around Intel processor and worth the extra cash if you can afford it. Older generations such as the I7-7600k are still available and very good processors. I won't comment on AMD offerings because of my lack of knowledge in them. When it becomes time to upgrade I'll look at them deeper. They have some very good offerings that may save you a bit of money and are worth checking out.
As for the GPU, I started my VR experience with the GTX 970 and with careful application of settings I could get decent performance out of it. I have recently upgraded to the GTX 1080 and I can definitely recommend it. Much better performance and graphics make the game very smooth. A nice benefit is in other games, I like to play FPS shooters and with the GTX 1080 I can run my 1080p G sync monitor at 144 fps on full Ultra settings without a glitch or stutter.
An SSD isn't required for gaming and I've never seen a benchmark that showed any improvement from having one, so a potential savings there. 8 gigs of ram is enough, I run 16 and feel that that takes out any ram related issues that I might have. As for ram speed, anything over 2666hz will rapidly show diminishing returns for the extra cash, getting a quality set of 2133 or 2400 ram and spending more on the CPU will be a better choice gaming wise. Also, some games show virtually no improvement in increasing ram speed while others do but I haven't seen any tests with done with Elite Dangerous.
Whatever the case, I would recommend getting the best computer I could and I would prioritize spending more on the CPU and motherboard if it came down to a really CPU/motherboard with a GTX 1070 or a average CPU/motherboard and a GTX 1080. The reason is you will likely change out the GPU sooner than the whole motherboard and CPU.