Whitelist dealership would be a fantastic idea, but the vehicles may have to be made so they can NOT be sold and/or only be quick sold to the dealership to ensure that they are not turned into another way of generating profit such as the current property market.
If Auctions ever become a thing, the Government could put up 'rare' and extremely low 'limited vehicles' (barn find, police seizure, special import) into these auctions with the intent of them being one time offer to the highest bidder. Allowing theoretically large scale bidding wars to occur, money to be removed from the economy but the end user also feeling like they have obtained something for their money.
This could also be combat by offering more variety of things for people to do in city, Specifically things that cost money but don't intrinsically 'give' you something. Think experiences and/or short term items. Melbourne Adventures is a great example of this as players are exchanging money for services, rather than physical goods.
Obviously this is dependent on the demand and usage of such items and/or services and is by no means a simple or overnight fix, but could definitely be a viable route to removing and/or relocating money from the economy while still allowing people to see their funds as being put towards something.