I have been flying the UDI U818A for a couple weeks now and it was alright, but it never felt super fast or agile. I recently crashed the quad and had to replace one of the armatures - that is what got me started removing parts. I removed the shell, this really makes this thing lighter and less a slave to the wind. I moved the lights on the bottom to the front for better identification of which way is the front of the quad. 3D Parts are for the prop guards and canopy. I hot glued these on and this has proven to be a lifesaver. In the event of a crash, the guard absorbs the crash and pops off (usually in one piece!). You simply glue it back on while you are recharging for your next flight. Edit 4/20/2015 - I added a version of the prop guards with a 20mm higher stance for better clearance in grass. I also added a version of the source for this so it can be easily modified.