On John Irwin's webpage, he gives directions and has pictures of the wheel wheel modification. The URL used to be:
http://irwin.home.texas.net/HomePage/wheelwellsx.html
I just tried it and got a 404 Error, but I have this site bookmarked and it worked just a couple of weeks ago. (An internet glitch today, mabe?) You can try this URL, though and see if it works for you. Maybe some else knows of another page?