I created this remix in order to be able to use a metal bowden fitting with 1/8 NPT thread instead of the plastic insert. The thread in the body is not "real" NPT, but a custom metric thread around 9.7mm (I found M10 thread to be too loose).
The "spacer" (or disc) is needed between the back part of the metal fitting and the filament guide in order to avoid a gap of approx 3.5 mm between the fitting and the filament guide.

Additionally, I had to reduce the internal diameter of the small gear (from 5.2mm to 5.1mm), as it was too loose on my stepper motor.

Update 20190613: Mirror versions added of the body and lid. These have not been test printed, so I am not 100% sure if the thread goes in the right direction. Feedback desired.