AM8 - 200x300 buildplate - 350mm Z height

As I was considering to convert my A8 to AM8, I thought it should be possible to modify the build plate area as well.
These are the parts I created in order to accommodate an Y carriage for a 200x300 heated bed, without having to cut in the Y carriage to make space for the motor in the original mounting position (and not having to mount the motor on the back of the frame).
Also, I increased the Z axis to approx 350mm with the standard X axis carriage, by using 550mm extrusions (requires longer