I have just purchased my 04 FX4 and want to start my mods. Anyone know limitations with respect to engine work and warranty coverage. I'm not looking to change out pistons or anything that drastic.

Any comments would be helpful.

 

Do a search about this first, there are a lot of us that have asked this about everything from lifts to superchargers.
Bottom line is, if Ford can prove what mod you put in broke your truck then its out of your pocket.