not sure I'm following you fully. Are you thinking installing VidOn's XBMC on Fire TV or Nexus Player might provide a better experience than stock XBMC/Kodi or SPMC? I'm not sold we'd get hd audio nor 3D on FTV or Nexus with VidOn's XBMC. Maybe worth a try to see what happens though.
For more you can check this infographic video