Don't waste your time trying to reuse the origional ones.. For what they cost get new ones and put a liquid gasket material on both sides to ensure a leak free fit the first time... There is nothing worse then finishing it all up and being excited to run it and try it all out only to have leak and have to tear it all apart again to fix it... Trust me, don't play around, spend the money and do it right..
Edit: also think about wrapping it.. The wrap is nice and keeps the heat down, but it also holds contaminents against the pipe making it rot out sooner.. I'm not saying in a year, but sooner then usual..
02 WRX.. "It's fun when it runs.. Problem is that it hardly ever does..."