just a part of that link i posted. Many people think well the light is brighter so they are better, well read this...
"The most dangerous part of the attempt to "retrofit" Xenon headlamps is that sometimes you get a deceptive and illusory "improvement" in the performance of the headlamp. The performance of the headlamp is perceived to be "better" because of the much higher level of foreground lighting (on the road immediately in front of the car). However, the beam patterns produced by this kind of "conversion" virtually always give less distance light, and often an alarming lack of light where there's meant to be a relative maximum in light intensity. The result is the illusion that you can see better than you actually can, and that's not safe.
It's tricky to judge headlamp beam performance without a lot of knowledge, a lot of training and a lot of special equipment, because subjective perceptions are very misleading. Having a lot of strong light in the foreground, that is on the road close to the car and out to the sides, is very comforting and reliably produces a strong impression of "good headlights". The problem is that not only is foreground lighting of decidedly secondary importance when travelling much above 30 mph, but having a very strong pool of light close to the car causes your pupils to close down, worsening your distance vision...all the while giving you this false sense of security. This is to say nothing of the massive amounts of glare to other road users and backdazzle to you, the driver, that results from these "retrofits"."