[devo]

Originally Posted by andrettifan

I have no doubt that there are folks with white cars and Xpel with no problems and perhaps it was the installer, although this one seems quite large (for Connecticut) and reputable. They told me that this problem is unavoidable because no matter how well the Xpel is applied, over time some dirt is going to collect under the leading edge. Think of it this way... you can without too much effort peal the stuff off with a finger nail; it makes sense that wind-driven dirt can accumulate under the edge. I am fanatical about car care and wash my cars very carefully, mitt-applicator, film to paint. Just my experience. I took the car to a professional detailer to have the Xpel film removed and he wasn't surprised by the black dirt lines.
BTW, you mentioned the PPF yellowing on white cars. On my car the factory film on the rear quarter panels had yellowed after a year, not much but noticeable. That was one reason why I had it replaced with Xpel.
I have a 2020 M2C (HS, not AW) coming and I will have the rocker panels and behind the rear wheels PPFd, but this time it will be wrapped AROUND the front edge of the rocker panel (just inside the wheel well) and AROUND the rear wheel opening lips. I like the protection against stone chips, but HS is a light color and I don't want to take chances on more black lines on the body, no matter how subtle they might be.

The factory PPF on BMWs and Porsches sucks. It yellows so fast. You are right in what you are intending to do and wrap the edges as much as possible. It's looks better even if dirt never got underneath.