Save yourself some money and frustration and buy norman420 spindles. They go for just over $100 ($115 I think) shipped. Cheaper than getting the 03+ spindles since most people will not sell them by themselves. The YFZ hubs WILL NOT work with norman's spindles. You need Banshee, Warrior, Raptor, or Blaster Hubs/Rotors. The YFZ Calipers will work or you could use calipers from the Banshee, Warrior, Raptor, Blaster. The master cylinder from any of them will also work. YFZ lines will not work without modification. They are too long. I know that from experience. You can also get cheap Braided Stainless lines from a Polaris Outlaw or Predator. They fit relatively well but you will need to fab a mount for the splitter (reguardless of which lines you go with you will need to do this) and the top part of the line is a little long and will need to be looped (under the hood) to take up some slack. I got my lines for $20 shipped for front and rears on ebay.
***Edit- Forgot to mention that Norman420 will also buy your old spindles back from you and save you a few more $$$$.