This remix will accept a MG995(R) Servo, This Servo is MUCH MUCH more cheaper than the ones used in original design (and have more torque also). Also I'm including changes to make a QUAD extrusion in Marlin 2.0.5.3 (tested and working !!!).
UPDATED (05/27/2020): Added a NEW idler MUCH STRONGER, this new idler uses two (2) M3 nuts for the spring screws, and one (1) nut for the bearing. This new design makes the construction more stronger to hold the screws in the idler. For the spring screw you should use a top washer and nut to tighten the screw in place.
UPDATED (05/27/2020): New body makes easy to tight the PC4-M5 fittings, MUCH STRONGER too.
Changes in MARLIN 2.0.5.3 to use 2 or 4 filaments:
In Configuration.h look for:
Uncomment the line bellow:

//#define SINGLENOZZLE

Ucomment the SWITCHING EXTRUDER line bellow and change the angles.

// A dual extruder that uses a single stepper motor
//#define SWITCHING_EXTRUDER
#if ENABLED(SWITCHING_EXTRUDER)
 #define SWITCHING_EXTRUDER_SERVO_NR 0
 #define SWITCH…