I agree with @db_Cooper, there are a lot of books on Speaker cabinet design, it’s not a simple field.
Basically ports and passive radiators do the same thing they let you tune cabinet resonance for particular frequencies this is used to compensate for rolloff in the driver.
Ports can generally be calculated IF you have measurements for a driver and know what you are trying to achieve.
Passive radiators are more complex, My floorstanding speakers have a 10 inch CF woofer and a 10 inch passive radiator for bass, with a mechanism to adjust the weight of the cone in the passive radiator so you can tune the bass to the room, because the room itself has as much an effect on the bass as the speaker does.
Setting up a Sub in a decent room so it’s coherent is difficult enough, trying to get “quality” out of a sub in a car seems like focusing in the wrong thing.