Don't be connned by this crap.
All they are is standard halogen bulbs. Putting a blue coating on them makes them appeal to Corsa owners, but reduces useful light output. HID and xenon are actually a con as at best they will be using xenon gas instead of argon, halogen, etc. to fill the bulb. It doesn't make them brighter.
If you do get more light generated it's because they use a thinner element that gets hotter and doesn't last very long.
If you do go down this route get one of the decent Osram type bulbs, but do expect short bulb life.