I purchased a pair of front mud flaps (Husky brand) and they require drilling hole in the fiberboard (?) wall of the wheel wells. The flaps came with self-tapping screws that are going to be fine in the screws that will go along the outside edge at the fender flare where they will anchor in sheet metal, but, I don't trust them to hold up in the fibrous material. I'm looking for validation of what I'm planning, or, ideas for a better way. I really don't like the fact that I must fasten to the fibrous material, but there's no other way that I can see. But, if it comes to it, here's my plan:

I am planning to install threaded inserts (like pop rivets but larger with threads to receive standard screws). The installation tool works just like a pop riveter and the inserts are a permanent fixture in the wheel well surface unless the whole flap gets ripped out by something unforeseen.

I await your responses with proverbial bated breath. Seriously, please tell me what you think (of this).