Hi Gents
Maybe not too relivant, especialy now that you are tracking down some later lights but i have morretts on my XM which as Peter has said also suffers in the lighting department.
My advise is this, you dont spend £400 on headlamps because your current ones are a bit dim, you spend £400 on headlamps because you like the look of the lamps but having said that the morretts are a vast improvement (mine have valeo lamps), they are now very good to drive with at night but i do have a slight critisism that may not affect the Xantia but having 6 H1 bulbs shinning away on high beam is fantastic, rabbits dont so much freeze in the headlights as drop down dead

, trouble is when going back to main beam it takes a while to adjust with the difference in light output being so huge, ive thought about HID'ing the outer main beam lights to compensate but decided against it, Ive started to dispise HID lights lately and BMW seem to be the worst offender of them all, whats the point in having such bright lights? all it means is the person coming the other way has to upgrade to equaly bright lights to try and see beyond you and you are both being dazzled even more being able to see even less at the crucial moment.
Maybe its because i live on i small island populated by idiots in BMW's who insist on driving down the middle of narrow roads nearly 2feet off their verge while im pushed up into the hedges my side all the while being dazzled by their HID lights, maybe as i get older i become more misserable who knows

. Anyway i digress, good luck with your lights.
D