We just got $1000 off a car by going through Ford credit. They 'suggested' we wait until we get our copy of the title before paying it off because that made things easier for us. They said that would generally be 2-3 payments. I am sure it was because the finance person gets her commission after 3 payments. However, they did not require 3 payments nor did we sign anything indicating we would make at least 3 payments and we specifically asked if there was a pre-payment penalty (there wasn't).
As said earlier, do not pay cash. If you have the money to pay cash, finance through the dealership, then pay off the car quickly. The dealership makes money on the back-end through financing. If you go ahead and pay off the truck quickly, you wont even see the finance charges. They will negotiate more on the price if they know you will use of of their lenders.
may be a stupid question but.. do you have less leverage when you have bad credit? Buying a used car i always felt lucky to even get approved lol. Can i still play "hardball" knowing my credit will make a salesman vomit in his mouth a little?
You have less leverage because a bank will charge a fee to give you a loan. 2 grand of the gross could go to the bank, making it harder to negotiate price.