I have used such a car conversion kit for my enduro, one on the bike and one on the helmet. It�s really bright!

Now I�m planning to use such a kit for my Z. Either as an extra foglight or to replace the headlight.
If you replace the headlight you have to rewire so that you have dipped headlight on all the time. Othervise it will get dark when switching from dipped to normal as the HID takes som 20 sec to get full strength and the dipped hedlight goes off direct as you switch.

A 35 W HID consumes about 40-42 W so it would be no problem to connect it without modyfiing the stator. And you get light as with 150W Halogen!