MGN12 rail M3 to M4 adapter

This piece dampens vibrations created by MGN12 rails on an alluminium extrusion thus reducing the sound.
It also removes the necessity for M3 T-nuts as the screw holes on the sides are M4 sized.

Everything is modeled with 0.075mm tolerances.

EDIT:
Added a collection of raised end-stop mounts to fit the added height of the carriage. Just take the one, which works best with your setup.