This is what comes with the bulbs from the distributer.  I don't think there's a danger of cracking the lens, and if you're reading this you needn't worry about the voltage at the back of the bulb.

but it wouldn't surprise me to find that high-wattage bulbs don't last as long as the stock bulbs.

	The industry accepted life of a standard wattage bulb is some 200-300
	hours.   Of course, some are going to fail earlier and some are going
	to last your lifetime.   Time to Fail is a standard bell curve around
	200-300 hours.   Typically, the life of a high wattage bulb is less than
	half that of a standard bulb.   Some are rated as low as 50
	hours.  It is heat and vibration that kills any bulb, and with a
	high wattage, there is much more heat resulting in a much softer filament
	which is much more suseptable to vibration.   When running high wattaage
	bulbs in smaller lamps designed for 55 watt bulbs, not only do you run
	the risk of cracking your lens, you significantly reduce the normal
	life of the bulb.   In addition, the condition of your charging system
	can influence bulb life.   What is the voltage at the back of the bulb?
	Is the regulator allowing spikes on the power?  
	Beyond that your habbits can influence bulb life as well.   Do you turn 
	your lights on before starting the engine?  Do you turn the lights
	off after shutting the engine off?  Both actions will cause spikes
	that can take out the bulbs prematurely.   Even normal operation
	of high load accessories like the air conditioner compressor or
	the heater fan, create surges on the power when cycling on/off
	that reduce the life of a hot bulb.   This is especially the
	case with high wattage bulbs.