The E brake fix thread, is Nethawks E brake fix/mod, look it up. It does use automotive brake pads, that you will modify. The pad material is thicker, so should last longer.
You can shim the E brake or adjust it, but keep an eye on the pad thickness, they do wear fairly quickly.
The pad number that I posted should work. ( as I stated I am not 100% sure though, but I would take it apart and look at it, your dealer should have the pads in stock, then you could compare them. If that part number is not in stock use Polaris part# 2203147, they are both E brake pads for the same E brake Assy, but I do not know what the exact difference is).
The parking brake Assy is the same one that is on a 12'.
The parking brake Assy is the same between the 12' and 13', the Polaris parts list shows the pad number fits the 12' XP/crew, but doesn't state that it fits the 13', but they have the same caliper part number?
On the 13' it states it is a parking brake Assy, that includes pads.