I have an 04 f150 reg. cab and just lifted it with a 6" procomp lift and put on 33/13.50/20 extreme a/t's. Trying to decide what would be best to increase the performance of the truck after these mods. What would you guys recommend a full system exhaust or regearing to 4.56 from the stock 3.73. I'm assuming that the 4.56's would take some work off of the engine with the increased torque and thus save alittle gas, again it's only an assumption. Would do you have to say or recommend I should do. Thanks guys.