That new car smell is great, but the first rock chip on the highway hurts. Keeping that paint pristine takes a full-front paint protection film wrap, which usually runs about $1800. Best time to get it done is right after taking delivery from the dealer, before the first road trip beats up the bumper.
Negotiating the film install is separate from buying the car itself, so treat it as its own project. Call a few specialized wrap shops instead of the dealer, and negotiate the price of the film before you talk about how you are going to pay for it.
Remember that the 0% intro APR for 15 months on purchases and balance transfers is a hard deadline, not free money. If you still have a balance left when those 15 months are up, standard interest will kick in on the remaining amount.