I installed a set of LED rings as an experiment on a damaged 2007 factory Xenon headlight from a wrecked car. The lights were not cut open in any way to install the rings. The LED rings are behind the factory angel eye rings. They'd probably be a little brighter without the OEM rings, but you can't tell there are LED rings in the headlights by looking from the outside. These LEDs are white when turned off, not yellow as many I've seen so the headlight appears totally stock when off.
They're fairly bright, though not quite as bright as the new BMWs. I'm no camera expert, they're somewhat brighter in person then the camera shows. They're hard on the eyes if you stare at them. The pictures I took in the basement tuned out as just a blob of light and you couldn't make out the rings so I didn't bother posting them. If someone knows what setting to set my digital camera to for better shots, please let me know as I've never been able to shoot good light shots when it's dark out.
Overall I pretty happy with the results. I want to let them burn in for a while to test the reliability before I do the mod on the headlights in my car.
These shots are in the shade on a full sun clear sky day around high noon.
These shots are in direct sunlight with the headlights facing south on a full sun clear sky day around high noon.