I'm seeing a lot of tech questions, but not much about the actual game LOL

Does anyone know how the cars and unlocks are structured? It seems that every event you win, you get an unlock for the car you are driving. And winning a championship, you unlock the car?

So after unlocking for example the Toyota Landcruiser, is it better to stick with the decked out Jeep, or start "over again" with the Landcruiser?