Originally Posted by poloka
I believe the consensus on here was Ford was cracking down on ANY modification from stock saying it 'could' void the warranty for repair IF the failed part was somehow related to your modification. Just build a good relationship with your dealer and usually they'll work with you. They want your return business. But if you blow an engine and you have a lot of power upgrades, they could say that put the engine out of specs and that is why 'blah blah blah failed cause of your mods' causing you to find a way to prove otherwise. Just be careful if you care about the warranty. If not, mod the crap out of it and make it your own!
This is pretty much spot on. I would imagine the only thing that wouldn't be covered after something like this would be the exhaust system. I doubt they could refuse to cover engine/trans/suspension issues due to a minor exhaust mod that has little/no impact on the operation of the car.