We're using the XTR gear display/junction box on our tandem. It's very simple to install, just unplug the cables from your current junction box and plug them into the XTR junction box. On a single bike, I have the Di2 D-Fly transmitter hooked up to an Edge 1000, but since I'm not always using the same screen on the Edge 1000, this is not as practical or as easy to read as the XTR display. Also, there are no problems putting the XTR display in an otherwise Ultegra Di2 system.