Then there's the issue of the age and type of bulbs in your wife's Golf that you replaced. Halogen bulbs, just like HID, dim over time. A 1 year old halogen bulb loses up to 20% of its brightness. Bulbs installed by the automaker are usually long life bulbs that are quite a bit dimmer than non long life bulbs to begin with. I replace my halogen bulbs with like halogen bulbs every year. The difference in brightness is astounding.
Likewise with your CBIs. The whiteness of the CBI can fool the eye into thinking they're brighter than your old bulbs. So can the age and condition of the old bulbs.
See Scheinwerfermann's posts here for more info on the human eye and whiteness: http://www.candlepowerforums.com/vb/...r-lights/page4