Do I need a Flexystruder for the TAZ 4?

General Hardware
3

Check out this review:

http://makezine.com/2014/07/07/review-lulzbot-flexystruder-flexible-filament-extruder/

In sum: You can print Ninjaflex on a regular extruder, but much slower and not as reliably. It is also not amenable to swapping materials.