You probably want to avoid using higher wattage bulbs if you can. They run hotter and draw more power, so you put the headlight fitting, the wiring and the lighting control module (LCM) at risk.
And a higher colour temperature isn't "brighter" - in fact lower colour temperatures have often been shown to provide better road illumination.
I've use the Halogen "plus" type bulbs (in my motorcycle) and they do provide a small gain in light output over a standard bulb but not as much as advertised (i.e. a 100 Plus isn't twice as bright as a standard bulb - the laws of physics dictate this to some degree!).
The only sure way to get more light on the road is to upgrade the headlights to Xenon.
