Tips on Buying Cars: Squirming out of a contract, bill of sale, drivers seat

Question
I agreed to purchase a new car.  I signed the documentation.  They didn't have the specific car I was looking for on the lot (I gave a choice of 2 colours), so they located one at a different dealer.  Now, here's where it gets tricky.  The manufacturer has an additional incentive that is only good until the end of the month, and only valid if the vehicle is bought AND delivered before this time.  Since delivery won't be until the 2nd of the new month, the dealer is going through with the bill of sale on the 31st to make it look as though it has been delivered.  This is fine, and I agreed to this setup.  However, I have since found a much better deal from a competitor (way to wait until it's too late - thanks).  I do not expect an answer in time, so I'm sticking with my current contract, but the question is this:  Had I wanted out of this agreement, could I have cancelled before the bill of sale came through?  Further, if for some reason I can't get the extra incentive from the manufacturer (which, by the way, I made clear was a necessary part of the deal - they claimed they couldn't put it in the contract but that I would definitely get it), what is my recourse?

Answer
Hi Ron
You could test the dealer by saying you do not like anything thats not 100% done legal...but will only if they match other offer...( test them )
your in the drivers seat and could cancel if thats your choice...
As for the dealer back dating the contract a few days it happens all the time to give the customer an incentive that may just have expired...
PS...is the Mfg GM ?
anyhow you have a good day Ron...your last name like mine must be Danish background right ?
Regards
 Ray