English (my) translation:
"Style is the conformity of an artistic phenomenon with its genesis-history, with all of the contextual conditions and preconditions required of its existence."
The statement on style implies Siemper's larger ideas of both objectivity and genetic methodology focused on and around the object. His concept of style maybe true of purely morphological comparisons, but it does not account for public (social-cultural) acceptance of style which requires a theoretical legitimacy to exist. Style in this context can not be created by form but requires a existential legitimacy of the particular Zeitgeist.