God, can your math really be that bad? If the state raises taxes on car dealers by 30%, as you say, and the tax goes from 3% to 4%, why would that require the car dealers to raise the prices of their cars 30%?
How did you get "the tax goes from 3% to 4%" from "the state raises taxes on car dealers by 30%?"
About your other point, sure some of the dealers may only raise prices by 29% and absorb that other 1%, but you're still missing the point. The consumer is still paying the full amount of the tax. So the dealer is taking less of a profit. He isn't PAYING any of the tax unless he's running that business at a loss. The consumer is the only one putting money into the equation unless the business is being run at a loss.
If you don't think only consumers pay taxes, let me leave you with this "If that car dealership doesn't have any customers and no business for a month, why are the taxes '0' for the month?"