Originally Posted by thekurgan
Spot meter is built into just about every DSLR, just have to enable it, Bro. White cards cost $3, or you can use a paper plate. White balance is most important for getting these comparisons correct and like people have said, these manufacturers are estimating the kelvin scale of their output. I'm thinking of ordering these, so I'll submit some photos; I'm still researching at this point. I think the brighter angel eyes are a better option in foggy situations, than the headlights.
I'd love to see some good photo comparisons if you decide to do it.