hi just my two pence worth
i believe speed passions are rebadged xerun esc not to be confused with ezrun which are sensorless brushless esc/motors .
my lad runs a 13.5t ezrun combo bought for £40 s/h and we are very pleased with it no cogging or running problems so far . OK its not in the league of the latest top spec gear but on slippery wooden floor it well capable of holding it own power and speed wise.
hope this helps if not ignore the above drivel
dave