The styling for the new Opel Omega is taken from the VE body and the Insignia concept car of 03/04, not the other way around.
The original design comes from Holden. The first model Omega was released in 1986 and resembled the VN body type.
The new Omega is also RWD to help it compete with BMW etc.
From Opel : "GM bosses have decided to proceed with a rear-wheel drive setup currently being developed by Holden in Australia to be used in the next generation VE Commodore". Does this mean the Opel is sitting on the Zeta chassis? I can't find any reference to the platform used.
After the Insignia Opel stated that they were not going to use the Zeta platform at all.
The 48-215 was designed in Australia but the original front end was woeful.
Only the front end was redesigned by GM in America. All models from then through to the WB Kingswoods were designed by Holden with the exception of the HB Torana, Rodeo and the Gemini.
The chassis design for all Commodores was "based" on the Opel/Vauxhall and the same tooling was used for the bodies though the bodies were widened by Holden on later models. Everything else is by Holden.
The VE is Aussie designed from the ground up. The V8 motors are assembled here using imported parts from GM subsidiaries, not Chev just GM.
Parts for the motors may have come from China, Korea etc.
Holden Commodores are unique to Australia and are manufactured in Australia.
They do resemble other GM vehicles but only the doors, lights, front guards, glass and bumpers are interchangeable. On earlier models the bootlid and bonnet are also interchangeable.
. The first Falcons (XM/P) are almost exactly the same as the American versions and also the same under the exterior panels as the classic Mustangs. The XW/Y Falcon can be still found driving around in decent numbers in Mexico and it's pretty much exactly the same as the Australian version and Ford used that same chassis well into the 80's . The Zeta was at first a German concept car, rendered possible production version shown above ^. Nothing is new 
