[lewislongbottom]

On your gusset plates holding the frame together, I think your hole pattern maybe wrong? It seems like the holes are too close to the walls of the tubes, most gusset plates have holes centered on the center-line so they don't interfere with the constraints of the tube. The amount of holes is over kill.

As for your belly-pan cutout pattern, you may want to simplify it. Its probably killing the performance of the CAD model (the time it takes to render every time you move the model). Its prob not optimized for all your electronic components either. But I assume you designed it like that to be FANCY!!!