Assuming that the parent means 2004 as the X3 with plastic bumpers and with headlamps with a single xenon light and without angel eyes (mine is from Aug 06), and the end of 2006 / 2007 X3 as the one with partially painted bumpers and with headlamps with double xenon and angel eyes, I'm pretty sure the headlamps mechanically fit, but will require a lot of electrical changes.
I've seen two X3's side by side and the lamps are exactly the same size. I haven't seen the engine zone to see if there was different cables tough
Please keep us informed if you change the headlights.
The 04-06:
http://www.nicedeals.co.uk/images/bm...ht-x-04-bp.jpg
The 06-07:
http://www.theautochannel.com/news/2...30379.1-lg.jpg