Democratic Alliance
The Democratic Alliance is particularly strong in the Western Cape area. They are a home for "opposition" voices. They have a shot at winning the Western Cape province, but they will not win the presidential election. If they do well but no party gets an outright majority in the Western Cape, then a provincial coalition government will be necessary. Unfortunately, the candidates for premier are not friendly toward each other, and it is hard to see effective coalition government.
The Western Cape is the most interesting contest, because it is the most difficult to predict. And, the DA is right in the thick of it.