Quote - Is it necessary to buy this models?

You don't have to buy anything if you don't want to. :) Technically, that's Stephanie Petite 3, usually abbreviated to SP3. There was a Stephanie 1, who was related to versions 1 and 2 of Mike and Victoria (she could wear V1&2's clothes). She too was fairly ugly out of the box, but can look good if you treat her right (see my gallery for an example). SP3 suffers from not being as well supported as her cousin V3, so you won't find as many clothes, hair and characters available for her. I happen to think her proportions are nearer the norm for the female population compared to the statuesque V3, but your opinion is the only one that counts. She can look good - check out Blackhearted and Rio's Irina character in the marketplace, for instance - but most of the character creation effort has gone into Victoria, sadly.