Like the Ford "SVT" type suspension on mine, have heard here recently that you can get the set with front assembled struts & rear springs & shocks for around $300 - not too shabby!
Used Tousley Ford to source mine (Steve is our "contact" there, though you don't NEED to talk to him). Village Ford is a new sponsor here (Andy) & I've heard good reports on them as well.
Make sure to get the '06+ set to fit yours, the std. SVT set needs an "OMNI" kit adapter set to fit the later cars because of larger strut diameter.