Marco:
Commander 950 Software, manuals, base maps, etc. are available at no charge from Holley:
http://www.holley.com/TechService/Library.asp. You can purchase a RS232 serial communications cable at any computer store (staples, Office Max, etc), however, since this is a running car there should already be a communications cable installed. You will need an older laptop, Windows XP or older. If you are not computer savy, saving files/inputting data/traversing menus/etc, you better find someone to help. Double check all files after changes to make sure errors were not created and save all files for reference. Also, get help from someone familiar with the Holley software.