Here is a thread that goes through a ton of detail about the process both front and rear.
http://www.gasholes.com/smf/index.php?topic=3232.0 I think it is after page 30 some where. I used this process and discovered that my car was in really bad shape. I used a .097 aluminum spacer under my rack to fix the problem. I have always read the .020 was the acceptible limit per inch of travel on the front. The rear will allow a little more, maybe .030 but that is it! The car will not handle as well if these perameters are not checked. Good luck. This is a big project. I worked on mine for a month!
