Know the confirmed part groups
The game page explicitly names batteries, motors, controllers, brakes, tires, and suspension as compatible scooter components. Use the current garage interface to see which specific parts fit the scooter you are building.
Change one setup variable at a time
For a useful comparison, note the scooter and the component you changed, then observe the result in the same kind of ride. This makes player testing easier to interpret while exact effects and balance are not documented publicly.
Avoid universal rankings
Voltline is still in early testing and the creator warns that balance can change. Without a verified current stat table, a fixed best motor, tire, or complete build would be speculation.