Ok, just to start, I understand the difference between the two. The big question I have is, do You think a Superchips Tuner ($499) is worth the cost difference vs a Speedo Calibrator ($149)? I am going to a 295/60/20 tire, I'm most interested in shift points and fuel economy (yes I know) that a tuner might provide. I know the calibrator corrects speedo, does it also correct shift points? I have a pedal commander so performance is a non issue for me.