I run the 4300K in my fogs which match the factory HID Low beams.
I run the Luminics yellow Halogen H8 bulbs currently for my angel eyes, which perform just like stock in the dimming aspect.
I have run the Nokya LED in my angel eyes before and if I recall correctly they did dim like stock. Not 100% but I feel like I would remember they flickered if they infact did flicker. I apologize in advance if I end up being wrong, I ran those sometime back in may of 2010 and have a hard time remembering what I had for breakfast let alone something that happened 7 months ago lol. I always recommend the Halogen Bulb route.