The green one is completely stock as designed by Boxx. It is a great design and a blast to fly. Unfortunately the crappy RCX ZMR 1804 2400KV motors kept throwing magnets which after one to many crashes onto concrete finally broke the frame. Let me say that the frame took more abuse than I ever thought possible and held up remarkably well. I liked it so much I decided to print another using some better motors. I am using an old naze32 in this one and I could barely fit it in Boxx's original design. There was no way to put the top on so I decided to remix it to better accommodate my electronics. I made a few other changes in an attempt to hopefully increase the frames strength by removing some of the sharp corners/ stress risers. That was the intent at least but I'm not really sure it made much of a difference.. The yellow one is the result and it flys just like the original. I have since changed a few things on the yellow one and am currently working on a top that will house an AIO VTX and GPS Rx. It was flying well with cleanflight but so far I am having a little trouble with INAV. It is a work in progress. I intend to post the remix files soon when I get the time in case anyone is interested.