I printed this and am a bit disappointed.
You shouldn't have changed 3mm to 2-56 ..nearly everything on reprap is 3mm and introducing another screw size was plain unnecessary.
The gears are too thin --- toooooooo thin...I have broken nearly 4 small gears off the original wide design .. .(about 100 hours of use each) .. and I don't think the thin gears will last
Your idler design is made with support .. why? you can rotate it 90 degrees and it needs no support.