It's worth noting for anyone that is using this mod with the auto-bed leveling, that software can't compensate for a twisted axis. You'll want to take the time to ensure that your ends are tight, square and as true as possible. If they are skewed, then the extruder end will rotate slightly along the Y axis during Y travel. This causes the hotend tip and the bed sensor to be a different Z heights at the front and back of the bed. The symptom that this causes is after a successful bed leveling, the hotend will dive into the bed at one end and be too high at the other. I spent a few days chasing down what I thought was a software bug with the auto bed leveling code, when it was as simple as straightening my axis.