Jerry signs an agreement to buy a car from Great Cars Dealership in Georgia. Prior to signing, the dealer tells Jerry that he will include new floor mats, a roof rack and upgrade the CD player. No mention of these additions is in the written contract. When Jerry goes to pick up the car, he is told that those upgrades will cost him $800 more. Jerry agrees to pay $400 and the dealer accepts and provides the items. Jerry sues Great Cars Dealership for return of his $400. What arguments can each side make regarding this dispute? How does the parol evidence rule apply to the agreement?