As has already been correctly stated - Stay away from pointing the wand at edges...
I only use the widest angle spray tip on my pressure washer, and consider this to be the safest... And I have never hurt anything using it either, in decades... All the narrower angle tips will actually drill into anything - even concrete pretty easy - if held on a spot long enough...
The ppf will clean up so much faster because it is plastic, but you still have to be mindful of it like anything else you are pressure washing...
I still spray down entire engines and compartments, the underside of the hood,(don`t touch that insulation, or if have to, just quickly from a distance), all the places in front of some vehicles that are accessible when the hood is up, and I never have had any issues... Just look at what you are doing and never spray directly at connectors, etc., intakes, etc., just use common sense...
Then, Immediately After, my Master Blaster 8hp Blower under the hood, start at top of opened hood and go down, get all the water off, then start the back of the engine and go forward, lots of hot air everywhere, so the water does not sit on it, then the rest of the compartment, to the radiator, etc., going forward from the back of the compartment, so you get as much water off and out, and not blow it all over the dried places again... Let it sit outside in the sun as long as you can, if possible, and the next morning, I spray a nice plastic renewer, etc., product all over the engine, etc., where applicable, and it comes out fabulous.. And, starts right up...
Dan F