That new car smell fades fast, and the fight to keep the paint looking showroom-fresh starts the second you drive off the lot. Between insurance, registration, and routine maintenance, running a car takes a steady bite out of your monthly cash flow. If you are looking to lock in that gloss, the best time to get a professional ceramic coating done is immediately after taking delivery, before the clear coat picks up its first round of highway chips and swirls.
You should always negotiate the price of the coating or detail work separately from the vehicle purchase itself, treating it as an independent add-on service. Dealership finance managers love to roll extras into a long car loan where you end up paying interest on a wax job for years. Instead, keep the car deal clean, get your best cash price for the coating from an independent detailer or the shop, and handle the financing on your own terms.
Remember that the intro window is a strict deadline, not free money, and any remaining balance left over when those 18 months run out will get hit with standard interest. Pay off the total amount before the clock expires so your coating does not end up costing you a lot more than you planned.