The WX-500 is basically a WX-950 without a display. Instead, it puts Stormscope information on a display you already have installed, such as a GTN-650/GTN-750, GNS-430W/GNS-530W, GNS-430/GNS-530, MX-20, GMX-200, KMD-150, etc.
This is a companion discussion topic for the original entry at https://www.avweb.com/classifieds/wx500-wx-500-system