I also have a evader st. I bought a very powerful nova rosi .12, went through the effort of converting to a pull carb, and now have the stock motor back in. I put the .12 in my onroad car. For what I do, go out and jump and bash, ect, the stock motor is fine. All the motor did was add more wheel spin or wheelies and made it more of a pain to drive. The gearing only allows it to go so fast. It was faster because the nova rossi spun higher rps's, but only really noticeable on pavement. My advice, buy rear tires, best improvement I made.