You just need a tool to talk to the PCm like an OBDXPro VT or similar($40-80 depending on hard wired or BT, etc..) and then you can use LS Droid or PCM Hammer to read/write/segment swap. You can then use universalpatcher or Tunerpro RT to do whatever tuning you want to it. All of that software is free. It isn't as user friendly as HP Tuners, but in some cases there is even more tuning options and tables that don't exist in HP Tuners. For instance, I have patched my OS to use Lean cruise, which you can't do with HP Tuners.What free software is this you speak of, Compared to getting HPtuner, which is gonna run several hundred