how much money were you willing to spend? i hate to see guys dollar a truck to death with little bolt ons that do next to nothing... by the time its all said and done you've spent $300 here $600 there.........before long you could have bought a supercharger. I guess what i'm saying is there is no magical combinations of bolt ons that is going to make a 5000 lb truck 2 seconds faster in the 1/4. Decide if you want a lot of bottom end or top end. There are several little changes you can do to give you more top end, but not much unless you want what i call a "real" modification. If you want pulling power thats peppy in town, regear.... Make a goal of what you want the truck to do and do what is necessary to make that goal. If your primary purpose is pulling trailers, then i'd regear. if you are already low geared and dont want to decrease the already low gas mileage......................there are plenty of '06 cummins on the lot like i bought last month