Slugstruder 1.0 - lightweight flexible shaft extruder

This is a lightweight flexible shaft extruder, that i designed for highspeed printing.
The idea was to keep the stepper away from the moving parts so not too much mass has to be accelerated without the disadvantages of a bowden-extruder. (i posted a early idea of ot here http://www.thingiverse.com/thing:6653)
Another idea was to replace the passive idler bearing with a active second hobbed-thing as well as using gears with a bigger diameter to garanty better grip when extruding at high speed.