Yeah, G4 are well respected for their ability to manage large scale projects, and they are well able to cope with short-notice changes.
For example quite recently the UK decided to put on the Olympics and with only about four years notice, ( "When? The what? Olympics this summer? Why didn't anyone tell us??") G4S (+Grateful 4 Soldiers) somehow managed to do such a sterling job that the Armed Forces had to get involved to get them out of the dog toffee.