Just bought my wife a used 2017 Platinum with under 30k miles, WAY cheaper than buying new now days! She heard something rattling driving back from the airport the other day, figured out it was the air deflector for the rear tire. Looks like the inner trim panel fastener broke and caused it to flap around at highway speeds. Took a closer look and apparently the original owner ripped the other one completely off and has been missing since we bought the vehicle. The part is like $30 do I really need it/what does it do as it appears to be easily damaged/broken. If it is just for aerodynamics I will decline replacement, but if it blocks road salt from accumulating on the underside of the vehicle I probably would. Any guidance, or suggestions would be greatly appreciated!