The 4.6 is not a good engine choice to begin with for a 4x4 supercab truck that weighs just over 5000k. The 3.55 axle is also inappropriate for towing. However, some aftermarket headers and a high flow exhaust will wake up your engine abit. I put JBA headers in mine a few years back and they are expensive, but they add about 20 horsepower. Check out the JC Whitney catalog online and you can find some low cost alternatives by Pacesetter. They have basic black, the cheapest, and for an extra hundred bucks they have stainless steel shorty headers that look really nice in the pictures.