This is true, the only lights your "legally" allowed to have is white or amber at the front and the same plus additional red for brake lights and indicators, that being said, a lot of headlights are starting to look blue anyway.
Also those ones are pretty overpriced, heres 10 for under 2 bucks
Yes they're very noticeable. See commodores with them all the time. Blue would also be a risky choice. I know guys who have been done for impersonating cops because they've had blue neons/LEDs