Does the SCT and Diablo tuners only allow you to make tuning changes through full custom tuning files that you have to get from people like American Muscle or Brenspeed etc..?? Does the PC interface allow you to go in and make adjustments yourself? Or does that constitute a whole new tune? There is another company out there called Delta force I think and their tuning seems to have more available options that the user can adjust. I just want to be able to change as many things as I can when changing around tuning settings. I know this has been asked many times but who's tuner does everyone like?