Installation:
Simply extract the files from the 7z file to your:
\Steam\SteamApps\common\The Witcher 3\DLC\DLC1\content\bundles
folder and run the .bat file.
(Game has to be closed)

Deinstallation:
Run the uninstall bat file.
Done.
(Game has to be closed)



Notes:
If you have not purchased the armor from the vendor before applying this mod, the armor will not show up at the vendor. I don't know if it reappears in a few days or not (I waited over two days and it didn't reappear). Purchase the armor and have it in your inventory before applying the mod just in case.

If you apply the mod before buying it and it no longer shows at the vendor, uninstalling it should make it show up at the vendor again to purchase.

The New Game + version of the armor has not been modified. It is unknown how the armor will be affected if the game is moved into NG+ in the future.

It is unknown currently how the armor will be affected once the game triggers it to scale up to level 29. It might only change the armor for sale at the vendor, it might change your equipped armor, it might cause errors. I am unable to test this right now as my character is level 25.

I do not know where the value for the level requirement is for the armor at this point, so last I check it was set at 21 for all versions.

I do not know what affect changing the version of the mod will have on anything you have slotted into the armor at the time, as I have not yet tested that. I expect you will lose the slotted runes, but am not sure.