Until now, DLCs & car packs anyone can buy are related to additional content. All enhancements of the game itself are done for all players or not done. This dogma has the very consequence of considering only what is considered affecting the maximum of players with no additional income for the project related to ‘already in’ players.
What about proposing some features expansion packs ?
I would pay for a Creator Power Pack allowing me to have extended garage/tunes/designs storage. It’s not pay for win, it is not cars or new map but, sure, I would put a few euros/dollars on it.
Adding that, same time it creates little incomes, success or failure of those are information to prepare next version.