Here is the most simple VATS fix.
http://cgi.ebay.com/ebaymotors/LOCKS...QQcmdZViewItem
Maybe call the number listed or e-mail the seller and see if you can just purchase the one that matches your key resistance. OR Here are directions on doing it another way.
How to bypass the VATS (PASSKey II) system in a late model GM vehicle
http://www.likeabigdog.com/column/VATS.htm
http://stores.ebay.com/Audio-Allies and search for Directed 652T GM VATS Overide Kit
Ray