I noticed that the XCAL 2 is pretty much the only computer tuning mod you need as it covers pretty much everything the computer controlls when it comes to HP gains except for the speed limiter. Question is, when it comes to shift times in a automatic, how do you know what RPMs to set the XCAL 2 to? How do you know when your car should actually shift to use all of it's power without overreving or short shifts?