As far as I know they haven't added S80 yet in KR, but they did just add Kamaels so I'd guess S80 would soon follow.
And obtaining the gear isn't the issue, it's the fact that unsealing it is impossible until clan arena is implemented. And if getting 6 cloths to unseal a low A grade set is impossible, what does that make S grade when it requires ~80 cloths?
The upgrade system is viable for weapons(at least to the point that you need elite B grade varnishes since they drop from Zaken/Baium), it's out of the question for armor though. I know of a handful of +6 Blue Wolf sets, you can't upgrade that to Majestic though, it has to be at least +10 and good luck making that.