Ron is correct.. boiling the light assembly in whater is what's been done in the import crowd. The heat softens the glue enough to allow you to pry the light housings open with greater ease.

If you want to put aftermarket lights in there, I'd recommend the Hella 90 mm projector lamps. www.rallylights.com has them. They're the same units used in the Saleen S7 and S7R endurance racer. Come in high and low beam units... bulb size is a bit odd, H9.

There may be a Hella HID version for either the high or low beam... can't remember which it is. Good luck.