New Guy-Rear Spring TSB Question

I am a Land Surveyor in S.W. Ga. I bought a new '10 TRD Sport 4x4 DC Longbed about a month ago for work. So far, it does the job better in almost every way than the F-150 I traded in. You guys have a lot of useful info on here. 3 things:

-Do I need the Rear Spring TSB or does this truck already have it?
-When business is good, this truck runs 350-450 mi. per week on asphalt, dirt and muddy swampland. Mileage is critical, off road ability is nice. That being said, do you guys reccomend any cheap or free mods for this truck.
-Are there any other Surveyors using these trucks for work?

 

How many leafs do you have on your truck 3

 

Thanks, it's got 3.

 

You need the TSB if you only have 3. My dealer didn't inspect anything.. they just did it. Take the TSB in with you and say that you'd like it done.