The problem is related to the current handling of your wires. If you exceed
that, something will catch fire if your fuses don't blow first.
Bulbs that look brighter [whiter] but are only stamped with a higher wattage
numbers are completely harmless. The ones that actually draw more current,
I'd be wary of those.
Most of those hyper white, HID looaklike, dychroic bulbs are nothing more
than a sham anyways. I don't care how much it costs, whether its a big name
like PIAA or whatever.
Take a look at this link and learn:
http://lighting.mbz.org/tech/info/superwhites/
Ken