I really like this suggestion, sounds good, but I would add the possibility for a dealership to sell even used cars. So once you get to a dealership you would be able to:
1) Give a look to the catalog in order to buy a new vehicle
2) Give a look around its parking lot / interior in order to see and buy an used vehicle.
This feature might create more opportunities for those who know how to run a dealership since they would even be able to create their own brand, you know, something like Brabus, that sells modified Mercedes-Benz / Smart / Maybach cars. With the possibility to sell used vehicles, a dealership owner might buy vehicles, modify them ( therefore apply sports preparation ) and then sell them under the name of a brand dedicated to the sports preparation of vehicles.
For example, here in Rome, when you head to a Mercedes-Benz dealership, you will actually see even Brabus for sale.