We found this extruder to be very usefull for the Diamond Hotend, as it will need additional extruding force, especially for the 3mm filament version.
We have remixed this extruder to include a 3/8" Push-in bowden mount and changed it to the 3mm filament. You can recompile it for the 1.75mm filament, but when setup as 3mm filament you can still use it for 1.75mm filament.
I have provided the SCAD files for others to remix.
Complete kit can be bought here: http://reprap.me/geared-extruder-kit.html