There is more to the color temp issue than absolute lumen output. There is also the sensitivity of the human eye to different color temps. As it happens, we are much less sensitive to light in the blue end of the spectrum (8k and up). So, even if a 5k was run side by side with a 10k, and they had the same absolute lumen output, you would STILL see less with the 10k bulb.
Blue bulbs look cool to those coming down the road at you, but if you really want to see where you're going, stick to 4300k to 5k. BTW, I'm running 5k plug-n-plays, and gave 'em their first test run last night...best mod EVER!