I've been running 9012 Silver Stars for a few years now. Probably the brightest Halogen out there. I've been waiting for a big name mfr to come out with a 9006 LED but haven't seen anything. Then I found Phillips makes a 9012 OEM quality LED and I jumped on it. They fit the Z32 well with the above modification. Just need to bend the housing tabs in a little for a snug fit. They are a little spendy, but you get what you pay for when it comes to bulbs.
I've heard that LEDs actually adapt well to projector housings like ours but I haven't actually tested at night yet to verify.