You are right it is a lot of money, junkyard would sell them to you for $15 bucks for both I bet.
I'm not totally sure about airflow in the wheel wells, but I tend to believe anything with a smoother surface has less resistance so a rounded well would probably be ideal (stock.)
The ones on my car, have integrated mudflaps in the front.. bummer! I found some that don't have that on there in the junkyard though, may have to switch!
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