Z axis support for Pursa i3 clone

This is a Z axis support for my modified Pursa i3 clone (geetech). I specifically built this to support the inverted Z axis (Z motors on the top). Without this support I have not had any serious problems so far. But, there has been lot discussion on several forms about how unstable my current setup is.

Check my youtube link for details about the printer without this support https://www.youtube.com/watch?v=hCBvofd2aF4

Check my youtube link for details about the printer with this support htt