I bought a roketa gk-06 off go karts usa and it worked fine i ran it for abought 1 month before the gearbox broke on my behalf i revved up the engine and poped it into drive acedently so i called to see if i could get a replacement part to was about $600 and i was willing to pay for it but then they told me they would cover it in my Warranty and even pay for 1 day overnight shipping when the part got here i realized it was the wrong part then i looked at the email i sent them and i sent them the picture of the wrong part so i called back and told them it was my fault and sent them a picture of the right part they did the same thing and shipped it to my overnight and told me i could keep both so i wouldn't have to pay to ship it back overall i was very happy with this website