Looking to update/upgrade my '69RR headlights but not sure of the differences in the various options. I would like lights with "halos" for daytime running. but these can be had with both LED and Halogen. What has me curious is what the heat sinks are for on the LEDs - apparently some even have small fans. Why?

Also, what are the difference in power draw and amount of light from the various options? I'm not planning on long distance nighttime driving so turning two miles of highway into daylight is not a necessity.