Get in writing the offer from dealer number 2. Go to dealer number 1 and state they have been great to work with and you want to purchase the car from them however you got a really good offer from dealer 2 and would like to not cancel the original order, however you are on a fixed income and that is a lot of money. Dealer number 1 might try to match the offer or throw in some free stuff such as maintenance, cool parts, mats, hats, etc. I had something like this happen to me on a slk 350 and the original dealership could not match the other dealerships price, but I really liked the dealership I had the car ordered from and got free goodies and a 3m clear bra on my front hood and grill area, so the price difference was only a few hundred dollars and decided to go with them instead of the dealership with the best price.