The hitboxes are the same, so to any seasoned player the visuals really don't matter gameplay wise, as long as the model isn't too out of scale with it's hitbox.
Unless there have been changes in the game, different cars have different hitboxes so technically in this circumstance you might be wrong. Not that there any absolutely amazing car for hitboxes, but there are differences and they affect gameplay.
I assume you're still talking about Rocket League? All models in that game fall under 1 of 6 hitbox types [1], each of which are attainable without purchase