I replaced both the headlight and passing lamps bulbs with xenon bulbs. Needed to accommodate the ballasts behind the neck cover on the left side and use a separate relay for the lamps and headlight. I wired them myself using the original passing lamp switch and for the headlight I used the hi/low switch. I have converted a bikes lights before and never used the hi-beam even when travelling the back roads in the everglades so this time I didn't worry about a hi-beam.
I just wired the headlight to the low-beam setting of the standard switch and the hi-beam setting is now an "off" position. That way, if I forget to switch it on I have a blue indicator light on the dash telling me so.
In a pack of 6 bikes I can be at the back and still light the way for everyone without blinding them in their mirrors. Also, I never get oncoming drivers flashing their lights to tell me to "dip" mine so no problem there.
They look the same as the high end cars with the blueish light. It really is a great setup.
As a bonus they actually draw less than the halogen bulbs after the initial startup but, as stated, you definitely need to run them through relays.
Since I bought mine the price of this system has really dropped and they are readily available at auto parts stores. Let me know if you go this route and I can be of help.
I have been stopped loads of times at bike events, several times at Biketoberfest, by people asking about my lights. (It's always nice to be different.)