Does the 350z have HID's?
I'm assuming that's what you're talking about, in that case you would just need different temperature bulbs.
6000K is white, 8000k is blue. I wouldn't go above 8000k because than you would start to get a purple tint. If that's not what you're talking about then...ignore this post.
And also, the higher temperature the lower the brightness.
Here is a link to purchase some Xenon's. Although if your car didn't come with HID headlights, I wouldn't get the kit.