Originally Posted by Chill72
You replace stock bulbs with hid ones, of course that requires a power source ballast and resistors. It's fairly easy to install if you know anything about electricity or how stuff works...if not there is a step by step video in M3 pics/videos forum in a thread titled "I'm Blinded"...and this video shows work done on M3 and not other BMW. I'll should have pics tomorrow.
Bear in mind that the same uneveness of the rings is still present using HIDs as with your OEM incandescent bulbs.
The only change is that light output at the rings is at a higher intensity than stock, with the cost being a much higher temperature (referring to heat, not color) within the headlamp housing.