I have the Xcarlink. Works great not only for MHD Gauges but I use it to display my Escort 360 Radar Detector. I mounted the detector in the back of the car and bluetooth to my phone. Then I mirror the screen to the Xcarlink and presto it's a super stealth sytem.
Interesting, I assume you purchased a dongle for the screen mirroring? I got an HDMI dealio from them, not sure if that is the same thing or not.