and it shouldn't be done in the stock 00-01 halogen reflector headlights, as this will cause you to blind oncoming traffic because the headlights are not designed for HIDs...you would have to either custom fabricate projectors into your headlights, get the ebay projectors and swap in some HID projectors and get an HID kit (~$600-$700), or get the 5.5 gen (2k2 to 2k3) HIDs (you can find them for around $600 as well)..
Obviously the best for light output would be HID projectors, but IMO the 5.5 gen HIDs look the best...
EDIT: I hope nobody kills me for posting this here, but for the sake of saving the original poster some $$$, here is an excellent group deal going on. $90 for a pair of 5000k d2r bulbs (which is what you want, trust me)
http://forums.maxima.org/showthread.php?t=484498