Amir: I used your beefed up quad design but added some more blocks to the bottom, which seemed to help with the stability. I am a civil engineer, but if you have a mechanical engineer on staff that could optimize a design for stability, I think that would help a lot. I think weight to power and center of mass needs to be optimized further. If you had a really solid design that optimized stability and durability I think you would improve your customer's experience out of the box.