RE: xl5?
xl-5 esc wont work with the stock vxl motor.
the xl-5 esc and motor will work, but as syco said...not for long. I think the esc will be ok, but the motor will burn up.
The only kind of brushed setup that would work would be a evx2 with a 775 motor....but then a 775 motor wont fit in the slash 4x4.