Nighthawk X4S AC3200 WiFi Cable Modem Router (Model C7800) WiFi Range Extender

I am looking for a compatible (plug-in) Wifi Range Extender for my Nighthawk X4S AC3200 WiFi Cable Modem Router (Model C7800) that will not sacrafice speed or the advanced features that come equipped with this cable modem/ router combo.  I know that technology has been advancing quickly, therefore I would like to make sure that I purchase a range extender that will be compatible with any newer technology that will be hitting the market soon.  Any suggestions or advice would be greatly appreciated!!

Thank you 

JP