Oh man yeah
So for 18650 cells there is a physical limitation to the capacity of the cell (since 18650 is a size/form factor nothing else). You cannot exceed 3400mAh without safety concerns.
Panasonic makes the highest capacity cell at 3400mAh. Anything above that is a lie.
For electric hub motors the two important characteristics are:
If you know what the Kv is of the motor that's actually more important but that's getting technical.
Also if you get like an ASI controller or even bother to spend any money on a new controller, you can make it go faster :)