I have worked in auto financing for many years. If you want to play hardball you need to find out if your loan has been funded yet. Just because you signed the contract doesn't mean the dealership has been paid for the car. Call the bank - tell them circumstances will keep you from being able to pay for the vehicle - they will send the contract back to the dealer. Also call the dealer and tell them that you will not be paying the $1K down - because it is listed on the contract they can't go whining to the bank (banks HATE post dated checks for down payments). In this ugly lending market there isn't a dealer in the world that wants to **** off their banks. Oh and a 30 day trial period is an urban legend in most places - kind of like lemon law on used cars - doesn't exist.

Hope this helps!