Is there a tuner for gasser that can offer two different modes, one for increasing fuel mileage while commuting and another for increasing power/torque while towing/haling? The way it would work I suppose that it would be in a default mode to increase fuel mileage (but not as to choke it) and if I need power/torque I could just press the tow/haul button?

preditor...!

I am very happy with my tune from pcmforless.com. While it doen't have 2 modes, it did increase mpg and power-especially low end. I went from 12 mpg to 13.5-14. With my k&n intake and magnaflow single exit muff, I did over 14.6 highway. That's with a 6500lb ccsb with 285's, 6.0 auto. Hope that helps.

Is there a tuner for gasser that can offer two different modes, one for increasing fuel mileage while commuting and another for increasing power/torque while towing/haling? The way it would work I suppose that it would be in a default mode to increase fuel mileage (but not as to choke it) and if I need power/torque I could just press the tow/haul button?

Justin at Black Bear can set your tow/haul for different modes. I don't tow much, so I have "normal" tuned driving and when I press tow/haul it is in "race" mode-not ideal for towing, but more power/firmer shifts. He can set the button to do something different if you want. He goes over this with you (as I am sure other tuners do also) during the process.

I would go with a custom tune. They don't have a switchable mode but they can for low and high octane. Even on the high octane tune my 5.3 went up about 1.5 mpg.