You don't have to download individual skins at the moment. In the media fire portal, go into the car subfolder you are after and there is a green button up near the top right hand side "download folder". That will give you all the skins in the folder in one hit. If you do that close enough to race day that should be it... otherwise you might have to grab a late one individually.
EDIT apparently this only works if you have a paid mediafire account. Sorry for the bum steer.
Last edited: Feb 24, 2015