....
Noticing that the eBay seller refers to it as being tough ABS plastic and not "fibreglass rubbish", there is a definite advantage in a fibreglass front spoiler because it's easier to repair and, as my accident repair centre/bodyshop guy pointed out: If you have a stronger knock it is far less likely to cause more extensive damage by transferring impact forces elsewhere.
I've scraped mine a few times and it's been easy to repair.
I'm not knocking ABS plastics but just pointing out a difference. OSIR's latest version of mine is now ABS plastic.