[Perfectlap]

spending a great deal on the front or rear bumper seems like a waste of money. Sooner or later someone will get you from the rear or some A-hole in an SUV will back up onto your bumper.

for doors, fenders and hood I'd take it to a good shop. I've had to paint and repaint my bumpers at least four times. Some times I had it done by higher end shops sometimes the places that deal with regular cars. To tell you the truth from afar, only a well-trained eye could tell the difference. And even with the higher end guys I still saw slight imperfections here and there.
I guess if this a collector Porsche that sees very little if any mileage, the only way these cars can retain any value, then it makes sense to be anal about it. But a car that's going to be driven daily or regularly not so much.