The E3D is a little longer than the Robo hotend. The E3D also comes with a 3950 thermistor which is very close to the Robo thermistor. I posted https://www.thingiverse.com/thing:3180056 a shroud that takes into account the E3D increased length. The posting also includes a new hex file to be uploaded that has the 3950 thermistor table and decreases the z axis length to accommodate the E3D. Also included is the original hex so that you can go back. Just change the connectors and you are in business.