Why this upgrade? If you upgrade to an e3d v6 (like me) and want to print higher speed like 80mm/s+, your extruder may start clicking and skipping steps. So an motor upgrade can help you out. It will allow your extruder to push more filament more easily. In my case i used an Nema17 48mm. Because the standard extruderholder isn´t as perfect for the 48mm upgrade, i designed an new holding system which works great in my case, and also stabilizes the weight in the middle of the z axis. This upgrade also allows for cable managent, and a filament sensor holder. If you dont need the sensor anymore, like me, because it can be faulty on transparent filament, you can clip the filament sensor on my holder. But you need to extend the wiring from the sensor, otherwise it will rip of mid print.