John in NM
Bearings or brushes, those are the two parts that get hot.
An aggressive belt should be fine if its sharp, they tend to feel grabby, but I don't think that equates to more load on the motor. I would expect more load when the belt dulls and starts to burn, and a moderate to fine belt will be worse that way once they dull. But that is just a seat of the pants opinion, worth all that you paid