SummaryModified whpthomas' excellent Replicator 2 Extruder Upgrade thing: (http://www.thingiverse.com/thing:42250) to add Support for flexible filament for the entire path to the exgtruder Including a conic guide to the aluminum block, and a bump out for the gap in the drive gear, to prevent NinjaSuck. This preserves the rest of the design, including the clever built in support.InstructionsPrint solid, left and right versions attached. Add the arms and enjoy the awesomeness. This mod has been working like a champ now, printing Ninjaflex parts. Depending on how well your printer is tuned, you might need to drill out the holes, slightly. You want a close fit, but not too tight on the filament. Enjoy