About this 3D model
this is a derevitive of http://www.thingiverse.com/thing:10637 its a single print lm8uu holders for y axis. this helps with drilling the holder right in place, hence the extension along the y axis - these help to align ti perfectly. i did have to move the belt holders off center for the motor to fit, but it has no prformance effect, and has been tested on several prusa's by me.