I've located a 2004 305 hp dually, 6 speed, with low mileage for good price. Will be using this to pull a 5th wheel RV in the 35'-37' range. They range from 11,000 to 13,000 dry. With water, clothes, etc this will go considerably higher. Also for normal driving to and from work. Which programer will give me better torque, without any other mod except maybe exhaust? Or should I forget and live with stock power?