The reason for my reaction, is that this is the only forum I have seen, where it is not advized to have them on fullbeams. On the Norwegian Alfa Romeo forum, Nissan, Honda, VAG, Bimmers - they all say that is no problem. Some have had problems with delay, but that is due to broken ballast, or lack of electicity, or broken bulbs.
Ok, the lightbeam maybe wider, but eventhough you dim the lights befor meeting other cars.
There are discussions on having these kits on regular lights though, since meeting cars have problems with a much wider light range.