One of the easiest changes to the 101hero is to convert the direct extruder to a Bowden extruder. In doing that, you end up left with a large extruder shell that is more than half empty. This thing contains just the coldend portion of the extruder assembly and allows you to move the motor off the print assembly allowing for more stable operation and higher print speeds.

Note: I have not printed this model to ensure it is structurally sound.