Rally America rules can be downloaded here:http://www.rally-america.com/rules.php
in PDF or Zip format.
NASA rules can be downloaded here:http://www.nasarallysport.com/rules.php
It sounds like you are already started into getting the vehicle preped. The Focus makes a very nice entry rally platform IMHO and I am having the most fun in a car that I have ever had in my life (and I'm 50 years old.)
Here we are on the way to winning the Berlin Regional at the New England Forest Rally: http://www.rally-america.com/event.N...551&gallery=50
I believe that the "fat" in your wallet can be modified by your passion. Example; I have no passion for Bass Fishing so a nice Bass boat is something for which my wallet will never be fat enough. The passionate Bass fisherman OTOH feels these costs to be necessary, appropriate and justified.
Good luck pursuing your passion(s)!