You sir are now on your own. Seems that you have no interest in the expertise and opinions of the people who know what they are talking about.
just because you did not see sparks does not mean they where there. in fact you would most likely not see them. At high voltages and high RPMs the sparks are hotter and smaller and cause MUCH more damage. The reason it runs better now is there is less resistance from the com and brushes. have no fear this wont last long as your motors are about to eat them selves.