While it is true that you can easily bump up the electronic engines to a higher HP & torque; usually the fuel milage does not improve drastically. As you have already stated you would probably us it to get from ligh to light faster and to get onto the interstate. We tend to use up the gained hp and so the fuel milage stays about the same. Now if you needed the extra HP to get you up a grade for the load or weight that you have then you would appreciate the boost in HP & torque. If you were to be gentle and not ask for all the engine can deliver you could gain in mpg.
Mike, Amy & Muffin, Full Timers
RVSA Certified Master Technician
iRV2.com -Gulf Stream Owners Forum Leader
2000 Scenic Cruiser
99 Chevy Silverado 4 X 4 Toad
2006 Saturn Vue AWD Toad
NASCAR #3 & #8