As far as I know that is true. I have the JET DST tuner for my S10. It is really similar to tuner cat I believe. If you google LT1 edit or tuner cat etc.... They have forums for help with them. You could probably even find someone else who has a map that would work to get you started. If I were you though, I would go standalone. You can't tune on the fly with the stock ECU based tuners like you can with a standalone like Motec, Haltech, FAST etc...