Thanks for the info guys. I have 3 tunes in my Xcal2, an 87 octane performance tune, an 87 octane towing tune, and an 87 octane mileage tune. I actually get better mpg with the performance tune. I took a 462 mile highway trip and put in the mileage tune, and lost about 4 mpg here in Eastern MT, in a snow storm both ways. My modifications from stock are an Airaid CAI, Magnaflow cat back exhaust, single exit, and Amsoil synthetic in engine, tranny, transfer case, and diffs. I have a 4x4 with 4.10 LS gearing and run LT235/85R16 tires, which are about 31.7 inch. Last summer, I usually got 20-21 mpg on highway with the performance tune, and just recently received the mileage tune from Wayne that I had originally asked for when I ordered the Xcal2. I ordered it with the above 3 tunes, and received it with only the 87 octane performance tune, along with a 93 octane performance tune. Had to keep bugging him for the tunes I had originally ordered, with my modifications taken into consideration, and finally got them via e-mail attachment. Like Todd C., I'll keep the performance tune in permanently, unless I'm towing my travel trailer.
Gary