Ideally, both. They solve different problems. Xpel Paint Protection Film (PPF) is ideal for the high impact areas to protect against deep scratches, rock chips, and minor abrasions. While the Opti-Coat will add extreme gloss, shine, and very high chemical resistance to the paint. Opti-Coat is a long term replacement for a wax or a sealant, leaving your paint easy to wash for years instead of months.