More than 1000 engineers pored over the car, drove it more than 3.4 million kilometres in Australia and overseas, subjected it to minus-20 degrees and more than 50 degree heat and crashed it 79 times.
GM Holden executive director of engineering Tony Hyde said the $480 million engineering project had produced a quieter, safer, more reliable and refined Commodore than the VZ model.
However, he also revealed that the longer, wider, taller car is now more than 100kg heavier at 1690kg.
Weight gains were in the chassis up 33kg, body up 70kg, doors 5kg, exterior 6kg and electrics 10kg, offset by savings of 16kg in the interior.
Hyde said the added mass made the car stiffer and safer.
However, together with extra power and torque, it had also made it thirstier in some models.
The base model four-speed auto Omega is a marginal .1litres per 100km more fuel efficient than the VZ base model while the biggest saving was .4l/100km in the six-speed manual SV6.
However, five models with the new American-made six-speed auto from Cadillac recorded 0.3l/100km more.
While Holden will release a dual-fuel LPG/petrol Commodore later this year, a fugal diesel-powered model is at least 18 months away.
"We have a diesel engine on test in a Commodore at the moment, which we bought from Germany," he said.
"Its pretty good and we've asked how much, but GM (in Detroit) would have to make a decision and I have no idea how long that would be.
"In the current circumstances of high fuel prices where it is a pressing issue, it would still be 18 months to two years before we could have a diesel in a Commodore."
He dismissed suggestions of a hybrid in the near future.
"The car hasn't been designed with a hybrid in mind at all," he said.
Hyde was speaking during the second week of a three-week media launch program at their Port Melbourne headquarters.
Last week it was revealed the Commodore would come in seven models: the new base Omega, Berlina, SV6, SS, Calais and two special V variants in SS and Calais.
There will be five transmissions, including the new US six-speed auto, with all other transmissions upgraded.
This week, engineers have revealed a host of other facets about the new Commodore
- The body is 50 per cent stiffer than VZ
- Gaps and margins in the exterior panels and interior trim have been reduced
- Repairs will be reduced thanks to a bolt-on front module and hinged doors
- New flat-blade wipers will include washers
- The French-made windscreen is made of sound-deadening glass
- The headlight projections are whiter and wider
- The heating system warms up 15 per cent faster
- There are more air vents inside the cabin
- The glovebox is 50 per cent larger
- There are more storage bins and bigger drink holders
- The battery is now located in the boot with jump-start posts in the engine bay.