I bought the factory full front mask from the dealer, and I am glad I did. Dead bugs on that thing are a heck of a lot easier to get off than the paint.
As far as damaging your paint, I have had only one problem - I noticed the top edge of the front bumper is getting little scatches in it, but I don't know if it is from the mask or something else - I didn't really look carefully. I can barely see them, so I don't care.
I leave it on any time it is not raining.
If you leave it on in the rain and then let it dry out afterwards it will screw up your paint something awful.