This is a quote from one of the slic3r links:"By extruding more or less while moving (i.e. by changing the flow speed/head speed ratio) we can make paths thicker or thinner:" By definision, extruding more or less while moving is variable. Everything I have read says Slic3r can do this, and the photo rendering backs it up. The hyrel can not make that part in the photo rendering. Changing the control to make the machine capable is an upgrade.Ignore me if you want. I do not try to insult. I just can not see a person doubting what is an upgrade when they do not understand what the slicing software included with a machine can do, when the machine control itself can not do it.