performance in your tow vehicle is a big picture not just part. You need to do a few things to get the total gain out of it. First deal with the air comin in, go inexpensive just do the drop in k&n filter or go expensive and do the full cold air induction box. Second deal with your exhaust system open it up so it can breathe but not over kill. Most v8 trucks a single 3in system with hi flow straight through muffler, like( flowmaster,magnaflow) is perfect and third is the item you are asking about is a tuner, hypertech, superchip, all make agood product but getting the total gain is all combined into one big picture. All these things work together to make your vehicle perform at its peak with the best mpg. one more thing you wont see much of a gain when towing if you always have your foot in it be consevative it will improve.
.
