It depends what you want. Stock the SPE produced abut 68~6900 rpm with a 20X8 prop which give you about 17 lbs of static thrust. After my modifications I got about 7450 rpm with the same prop for a total of 20 lbs of thrust. As fat as the ignition that it comes with it is not a bad ignition yet it does not allow the engine to perform at its best. When I used the ignition that came with it I got several mid range popping sounds. So the engine did not run as smooth. When I changed to the Rcxel ignition the engine ran smoother with better transition and power. If this is your first gas engine then I would recommend you try it as it is from the factory it will be just fine. Just make sure that you set it up right. After you get the basics of how to operate and tune a gasoline engine perhaps then you can upgrade some of the parts and that is if you are not happy with the flying performance of your model.