Whatever the issue with the D3.5, the fact remains that people run them and get beaten by others with older motors. If you want kV rating, then increase your mechanical timing. If you want power, then get a Reedy Sonic (190W compared to most other 17.5 motors out there with 120-130W). It's all gearing and timing. I have a D3.5 in my SC10 and a first gen Tekin Redline in my RC10, and seriously, I don't see what all of the hubub is about. It's a 17.5 motor. It spins. Whoopie.