I'll put in my
unbiased .02. I've used alot of different motors from alot of different builders/tuners. Every now and then I'd get a fantastic motor, but if you are looking for consistently ballistic motors give eXpress motorsports a try. I am NOT one of thier team drivers and get nothing from them that anyone else can't get, matter-of-fact, the last pack of matched cells I bought had better numbers than one of thier team members had just received.
With all that said, John Williams and Jon Tag, the battery and motor gurus are very easy to talk to and more than happy to help you out any way they can.