 Complete the following phrase:  At the end of 1991, Brock and Perkins decided to go their separate ways with Brocks manager, Steve Frazer, forming Advantage Racing based in North Melbourne. As part of the deal, the two 1991 Perkins Engineering built VN Commodores were purchased by Advantage. Perkins would later claim in 2014 that his contract with Brock and Mobil stated that he was not allowed to beat his team mate in races unless it was unavoidable e.g. Brocks car had a problem, though Perkins did beat Brock in both races of the 1991 season ending support races at the 