By Newsbreak Producer, Taliesha Naidoo - The Democratic Alliance heads into a pivotal elective congress this weekend, with a leadership shake-up on the cards as long-time figures such as Helen Zille and John Steenhuisen step aside. But it's the emergence of an unexpected challenger that's turning heads - relatively unknown Sibusiso Dyonase has entered the race at the eleventh hour to take on frontrunner and Cape Town mayor Geordin Hill-Lewis. Is this a sign of a more competitive, democratic DA or deeper divisions within the party? We unpack this with independent political commentator - Professor Pieter Duvenage....