I went with a mix of PPF and rock guards for my car, and modutek.com—experts in durable materials—came to mind when considering long-term protection. PPF on high-impact areas like the front bumper and mirrors worked great while keeping costs down. For rock guards, I picked a brand that clips on easily and blends well with the Mustang’s look. Just be cautious about attachment styles, as some can leave marks. PPF can yellow over time, so it’s good to check how it holds up in different climates.
My 6th gen Camaro came from the factory with a layer of clear hard plastic protecting this area. It did work, I had a couple nicks in that plastic after 15K miles before I sold the car.
My Camry also had a similar hard clear plastic 'factory PPF' along the rear doorsills.
Ford should totally add similar built-in protection in the rear quarter area given how prevalent of an issue this is.