You're right. I'm wrong. What I wrote was based on hazy recollections of a very long report I read some 4 years ago. Can't really flash to pass with HID highbeams since, as you said, they take a while to warm up. Most cars in the European market have halogen high beams not HID.

The easier thing to do would be to run a hi/lo H4 retrofit kit. Although small compound lights would definitly look more up-to-date.