I bought one from Amazon, if this is the same part you're referring to: https://www.amazon.com/dp/B00G0OLHIY/ref=cm_sw_r_cp_apa_fabc_S587D9M06DM3BCGG4F3E?_encoding=UTF8&psc=1
As for snow messing up your car... not so much. The cover's purpose is to protect things under the hood from road debris and excessive dirt that could contribute to faster wear/tear. The cover also helps with the aerodynamics of the car, believe it or not.
Edit: it doesn't come with the rivers/clips to hold it on, so make sure you get a pack of those too.