I put a HID in my dip beam, i got it from hids4u.co.uk or sumut like that.
Do a Google on it, half the price of most others and good stuff ie, the ballast on my set up is a Panasonic and the tube is Phillips. About £130-ish i think.
I do not think it is worth putting one in the head lamp as well as the reflector is so crap you will not get much from it, don't think i have used the headlamp since putting the HID in the dip. Mind i do have a a pair of Piaa spots as well.
Lyn.