I just bought some 100-watt 5,000k Xenon headlight bulbs on eBay. I know the kelvins (color temp) doesn't matter but is 100 watts too bright or against the law? anyone?

 

Anything but stock replacement headlights are concidered illegal. As long as they arent a blue or purple cops shouldnt give you much of a problem

 

Yes, anything above 7,500 kelvins is illegal in any state. I'm just not sure how many watts are allowed.

 

Illegal

More!

THIS is a good one

 

100watt units will run hot and probably melt your housing as well as damage/melt the bulb socket. Higher wattage doesn't make a better bulb, may be a bit brighter but I bet these bulbs have a good blue coating on them with in turn will dim them down a bit. Also hotter bulbs with tinted/painted glass are more likely to burn out (melt the glass and leak out the gass or explode the glass) and provide less useable light than oe bulbs. My buddy had been purchasing "lifetime guarentee bulbs" from Procarparts, one night he had not one but BOTH bulbs blow out in a second of each other right infront of a cop, he said when he took out the bulb it was curled into a finger shape...

The links posted by Kar are good but pointless when the OP was talking about HALOGEN bulbs not HID....

 

His original post was filled with mis information. standard bulbs are NOT measured in kelvin. period. Xenon bulbs are "look alike" bulbs, NOT true HID's
They are measured in watts. anything above 60 watt's is HOT for high beam. and above 55 for low is in the same area.
He needs to decide what he's talking about.... You can upgrade your standard bulbs with a higher wattage xenon bulb, and have no real problems....other that melting your factory harness. (use a relay and upgrade your cables)
So, see.... my links were not pointless! read carefully my friend!
And Merry Christmas