New motor and esc, which one for slash 4x4

[Justingt5]

Hey people,

I have a traxxas slash 4x4 ultimate with velinion 3500 setup but either the motor or esc or perhaps both has gone up it and I can't get the purchase invoice from the first owner to get it done on warranty?

Questions are mainly, which setup to go for, I want a kit that will be better for both performance on indoor astro track whilst being robust enough for bashing?

What's better, sensored or sensorless motor as I had an issue with cogging on the standard velinion motor and I've heard that a sensored motor is better for this not happening?

All help and suggestions greatly appreciated