Only problem now is that HID is almost impossible to find for a quad no less a z400...I think i'll stick with the ones on eBay...there really bright and sure as hell good enough for me...30W to 50W, hell that ain't one bit bad.

 

piaa has them.might try their H6M atv bulb.35w bulb that gives light of a 60w bulb.think they cost like $27.

 

With HID you would need to add ballast and I'm not sure the stock electrical system could handle it. Besides, it would be very $$$.