Sorry for bringing up a slightly old post. But i thought i would throw out my own solution to burning out angel eye problem for the do-it-yourselfers.
I just threw a 12v reglator, a MC78T12C, inline with my angel eyes and 95% of the time they see a cool, clean 11.96 Vdc.
Yes its a bit overkill being rated at 3A and they are ever so slightly dimmer because of the lack of voltage but its not really noticable.
The other 5% is when my car is off and battery voltage drops below 12.06v so they see even LESS than 11.96 but never more than.
I have a TON of home-made LED projects in the works and thats what works for me, take that as you wish. To each their own!
'94 Bonneville SE - 106k miles 6/1/07