Perhaps I am search challenged but I have searched the threads, read a boatload of posts for the last couple hours but I can't find an answer to these questions: Can someone explain lighting and light bulb specs to me? For instance on my 08 TL the DRL are 9005 or HB3, 60w. The bulbs that I find for sale all seem to be 60w. Isn't wattage the spec that defines brightness? What are the differences between 3000K, 4000K, 5000K, and 7000K bulbs? Thanks in advance.

 

No sir; Lumens should be what you want to research.

Lumens are the actual measure of brightness.
Kelvins (ex:6000K hid kits) are the "color temperature"
Although these are usually proportional to eachother; the higher the Kelvin temperature; the lower the lumen output.

 

Higher the Kelvns the "whiter" the light?

 

yes, to a certain point.
after about 5000 kelvin it turns blue.

 

yea.Cars that come with Hid kits stock; usually use 4300K which is the whitest color visible to a human eye, up to 5000K i believe?
BUT the higher the kelvins not necesarily whiter:

::2500/3000K is the lowest HID kit available i think? Which we use normally as foglights.and as you can see^ produce a YELLOW light. these produce the highest brightness/best visiblity. If you're looking for HID kits for the low beam; I wouldn't use anything more than a 6000K or 8000K(Bulb Size: D2S )