I like the design, simple but it works. Also i added a spring system to the model as i'm interested how that works. Yes it works, probably not that necessary as the extruder isn't the noisiest part in the system by long shot...
Got the idea (and OpenSCAD code) for the spring here: http://www.thingiverse.com/thing:1436572
Red PETG, 0.5mm nozzle, 40mm/s print speed