I was a diesel tech, rebuilt everything from large boat engines to monster generator sets as big as a house, flying about 30 plus years, I have build about 100 nitro helicopters, This Synergy E5 is the best built. I got back into this hobby 6 months back, i look for months to find a ship that i could fly and it not fall apart or strip gears. There is one part i would add to the kit, a small plastic ring to snap over the tail shaft gear, the one with the pin in it, and same with the trans gear pin. So if some forgot to tighten the allens in those, the ring would still hold the pin in the gear. I read here it does happen.