Why it is hard
- Compound curves. Window trim bends in two directions at the corners. Vinyl has to be stretched and relaxed in the right sequence or it lifts.
- Exposed edges. Every edge faces a squeegee, a brush or a fingernail for years.
- Trimming in place. The film is cut on the car with a blade a millimeter from paint and glass.
- Post-heating. Stretched vinyl remembers its shape; without proper heat it shrinks back within weeks.
DIY reality
Precut kits exist and they get you 80% of the way on flat pieces. The corners of the window trim and the handle recesses are where kits fail, and where a blade slip scratches paint.
Professional version
A morning in the bay, trim removed where the car allows, branded cast film, post-heated and warrantied. Reversible when you want the chrome back.