Halogen lamps and their globes must comply with ADRs 46 and 51, while HID lamps and their globes must comply with a different set of requirements within ADRs 77 and 78.
Interchanging globe types (such as putting HID globes into a lamp designed for a halogen globe) prevents continued compliance of the lamp/globe assembly, making it illegal.
Note that the ADRs do not actually mention projector lamps, but they are very specific on the light patterns provided by the lights, so it is possible that a correctly designed reflector headlamp could use a HID globe, like the Mercedes mentioned above. I am only saying it may be possible, but I dont think its likely.
I'd say it was just a kit like the commodores use, in a normal headlight, which is why it bothered wraith.
The reflector headlamps on commodores and virtually any mainstream car on the market are definitely not designed for HIDs. Commodores fitted with projection lamps are.
Also, ADR 13 requires that all vehicles fitted with headlamps (including HID) producing over 2,000 lumens have a self-levelling system and headlight washers. Adding HID globes doesn’t provide these features and are therefore illegal for road use.