About this 3D model

UPDATES 2013/09/30 After printing out the rest of the parts, I discovered a small error in the design of the front plate. I have fixed and replaced the STL. 2013/08/22 My print bed is maxed out at 150mm x 150mm so I redesigned the large parts starting with the chassis plates. The chassis is now in 3 parts that interlock together. The side guards are in 2 pieces that slide together. For extra support of all the pieces, I created a slot in the side guards for the chassis to fit in. All the parts should be printed without support material. I created breakaway(cut away) supports directly in the model. If there are any suggestions as to further improvements, please comment and I will see what I can do.