You'll lose the same amount when you come to sell it on in a few years, so at best all that you will save is the interest on the "discount" for being Cat S. Against that you'll probably pay more for your insurance and Tesla might not fix any bodywork related issues. At worst there may be hidden damage that has not been fixed but will only become obvious at a later date. Personally I'd avoid buying a car like this from a private individual who you have no comeback against. If the seller were a trader you'd be in a stronger position.
