If you have not made any modifications to your truck, it is probably a good idea to extend the warranty. If you have a tune or suspension mods, I would not spend the money as most dealers will not honor the warranty on modified trucks. (rightly, so)
I would say the big item is the tune, potentially setting up battles on if X, Y, or Z fails on the powertrain.
For suspension, the setup is pretty robust as is, so I would still think the extended warranty would be worth it for the electronics and engine/transmission.
Seen some people say the dealer declined stock shocks that leaked under an ESP and some say they changed them out no questions asked.
