You're all forgetting these cars are sold over in towelhead land as Chevrolet Luminas, coming out of the showroom wearing Chev badges, and have been since the VT.
The chev badges and grilles are produced for these cars, they arent tacked on from another car.
While Im aware we are in Australia, you can blame Holden for putting ridiculously oversized badges on, thats my reason for swapping to the more subtle Chev badge. It looks much better and with mine colour coded to my paint they are nice and discreet.
Id be happy to go completely badgeless but the holes behind the badges prevent this option.
As for whether they are GM or Chev engines they are essentially the same company so it's a pointless arguement.