I've read that autosocks should be used for both front and rear as they provide less grip than chains do. I have also seen autosocks getting severely torn after a use or two. So if you want something longer lasting than a single season, chains would be it.
amazon.co.uk has the same chains as Tesla's. Search for Maggi Trak 4x4LT51. Amazon jacked up the price severely due to winter, but they were on sale before winter hit for a lot less than Tesla's store.