You're talking about two different monsters. A filament buld, and a high surface brightness multi-chip LED.
1) You'll get a horrible beam pattern from the stock headlight reflectors. They are designed to have a glowing coil to direct light from, not a flat, bright surface. So you'll need a new reflector or optic for the P7/MC-E.
2) The P7/MC-E LED is a huge heat producer. To get any kind of extended life from it (read: more than a few minutes at full power) from it, you will need a large, heavy, finned heatsink, with direct access to airflow. Fans do not work well in the dirty world.
3) Assuming the stock headlights have a 30 watt bulb, the P7/MC-E should be able to put out as much light, if not more. But, perhaps a SST50/90 would be a better idea, more output potential. However these LED's also create lots of heat, so they need even more heatsinking than a P7/MC-E, at maximum output.
4) I'd think that your best bet would be to remove your stock headlights, and wire in new, brighter units, with multiple P7/MC-E's or multiple XR-E's.These will require lot's of heatsinking mass and finning, but multiple XR-E's will be easier to set up optics/reflectors for. (Think: a set of 4+ XR-E's on each side; one with a flood optic[40*+], one with a less floody optic [20-30*+], one with another tighter optic [6-13* range] and a very tight thrower optic, such as an aspheric lense.) The unit will be larger in size and weight, but will allow for both close and long distance illumination.
5) You'll definitely require a driver, witha 12-18 volt input range (this will allow for voltage spikes at start-up, high rpm's). And you might want to consider a two or three mode driver, to allow for selectable output's.
