I have never run across a dissappointed ro disgruntled go engine customer. I have yet to hear of anyone complain about lack of power or short engine life. That in itself says alot about the quality of them. I know not as many people run them and some look at them as a white label mill, but in all honesty i couldn't be more thrilled with the 3 i have. I will continue to run them for the forseeable future. Hell my truggy was able to keep up with a mugen mbx6 buggy with a ninja on the local track, that in itself says alot about the power these things make.