Originally Posted by 2012sel
I don't know for sure, but I'd wager it's for sound deadening and aerodynamics. It appears to be the same material used inside the wheel wells. I've seen that this material has been in use by Ford for a couple of years.
I think it's a sheet of plastic with a textured felt covering. Only time will tell on it's lifespan.
Yah, you're probably right... on all counts. That stuff is in my wheel wells ('05 ST) and I've never liked the looks of it, esp in the winter when there's sometimes heavy icicles hanging off of it... but it's still there and seems to be doing fine