This is the way 👍🏻

 

I swear, these plastic under body covers are the reason Fender Washers were invented

 

In my case the piece that has thread was missing. Only slot left. I think this is the piece Thomas-S has in his post is what was missing. It turns that M8 rivnut fits perfectly and swages in place nicely.
I even found made of AL!
10,000 mi and still goes strong.

 

What does this cover protect. I just noticed the drivers side (LH) one on my car is hanging down a bit.
Thanks

 

Brake and fuel lines, I believe. Fuel lines and filter are above the driver side cover, US. Serve as aero covers and splash shields as well.

 

Thank you....