Used Cars: bad move, finance agreement, spot delivery

Question
so, we signed the contracts and finance agreement that night and we took delivery of the car by driving around the block, and after thinking about what we had just done, we wanted out of the deal. after looking over the credit sale contract, i noticed that my signature wasn't present anywhere on the paper, although my co-buyers was, is this document valid without the buyers signature, only the co-buyers? also, they asked me to bring in a pay stub to validate my income, which i have not yet supplied. they are also missing a lot of our references for the financing. i went down there and talked to them and they said we couldn't just walk away from the deal. if i don't supply them with a pay stub would they be unable to finance us thus voiding the contract? is there any other way out of this? thanks in advance.

Answer
What the dealer did is called a "spot delivery" in other words they let you take the car home before they have been paid by the bank. What the dealer has right now is a contract between you and them, once they collect the necessary documents the bank asked for then the bank will buy the contract from the dealer for the amount shown on the "Amount To Finance" line. If you didn't sign the contract they got nothing period. If they are requesting additional documents they don't have what the bank has asked for which means they wont get paid until you provide what they need. You can just walk away from this deal but be prepared to lose any down payment or trade vehicle. The dealer can charge you some fees for driving the car but they cannot force you into validating this contract. If you still feel the dealer is trying to force this contract call the finance company and ask for there "Funding" dept. Give them your name and the name of the dealership then explain you situation to them and I would almost guarantee that they let you out of it.  No bank wants to loan money to a customer that don't want to buy a car. They wont pay the dealer knowing that you don't want the car.  
Hope this helps. Good Luck, Shane