Would be interesting to see the actual performance - it shouldn't affect it much, because the radar already goes through a layer of polyurethane (thickness unknown) and PPF is generally made of polyurethane as well, and only adds another 8-10 mils (thousandths of an inch). If it's just tint that's even thinner, but actual tint is usually more delicate than PPF and particularly subject to damage on all that front-facing real estate. Probably the most significant effect would be to the heating coils, since the PPF would add a thin layer of insulation and it might not be quite as effective at removing ice and snow. How hot it gets might also be an issue, if it gets hotter than a sunny day, since that might cause the film to separate. Hard to tell re-the performance, since you would need to test in identical conditions with an un-filmed car and see if there was a different reaction/detection time for the front radar, but I doubt anyone has tested it.