we would run out of water quicker
Governments would lose control of the masses and total anarchy would take over.
there would be no more of those cars
people would be crowded by horses droppings
Everybody would buy trucks.
Instead of roads, Venice has canals. A car would sink.
Cars are made of solid material because any other state of matter would be impractical for this application. Fluids like water are unable to hold a shape, but instead fit the shape of their container. If a car was made of fluid, it would lose its shape immediately, and would be un-drivable.
Water -powered cars. You must explain how these would work, because I'm not aware of any "water-powered" engines capable of moving an automobile.
no life on earth
oil spills happen because people are careless and and instead of emptying there tank they dump it in the ocean and cars driving on beaches.
things we shut down, many cars would not be able to run and we would melt
There is no limit. Finance depends on your creditworthiness. If you were Bill Gates, you would easily get a million cars on finance. If you have no job, no income, then zero cars will apply instead.
Technology would never existed, like the device you are using to read this answer, bicycles, cars, etc.