ZB engine bay vent added in 2021 was unverified.
Not the same specification as 2020.
On that basis, it would have been logical for 888 Race Engineering to come back and homologate a better aero kit for the start of the 2020, while hitting those required numbers.
The adversarial approach taken in 2019 has set off relations with Ford Performance on a bad foot indeed. Rushbrook even had to come out with a mid-season statement: "We will not accept any more changes to our Mustang package."
It would have been a far more sensible move for Supercars to ask 888 Race Engineering to go to the drawing board and come up with a better aero kit for their ZB Commodore for homologation for the 2020 season (if Kelly Racing wanted to continue with the Altima, they could have developed an up-to-date aerokit for the Altima too). After all, Ford Performance were specifically told to "build a better car (while hitting the VCAT drag and downforce requirements)" by the Holden homologation organisation so they did it, so for the rival homologation organisation to then complain about that afterwards is just bizarre.
For its faults, at least Group A was a fair competition between Ford, General Motors Holden, Nissan, BMW, Mercedes, Audi etc. They always had the opportunity to develop their cars to be
as good as possible. To bring out the next "500" or "Evo" of the Sierra or of the Commodore or of the Skyline or of the M3 or of the 190E 16V or of the Audi V8 with improvements to the breed of motor car.
The looser requirements of World Rally Car and Super Touring where more changes could be made to the best car also worked fairly well, up to a point. Though it was always baffling why the Lancer Evolution 6 and its actual yaw control -- so superb in Group A -- never amounted to much when Ralliart moved to WRCar (and the Lancer WRCar based on a base model Lancer, as they all were), even to the point where the Ralliart team replaced the electronic differentials with mechanicals one at one point for some reason (I don't recall why).