Technically what ever you modify voids the replaced part's warranty and anything it directly contacts. If you replace the headers the header warranty is gone along with the rest of the catback exhaust as an example.
An intake would void any of the intake parts of the engine but not the engine itself.
Ford must prove that what you did caused any issues they refuse to fix. That is in a perfect world. Basically if Ford or the place you take it doesnt want to fix it... they wont. You pretty much are at the mercy of the dealership as if you try to fight it you will simply lose regardless if you are right or wrong.
I would talk to your dealership, and if worse happens you can always put back on the stock items and take it in. They can also tell if a tune has been in the car or if it currently has one~
Most have good dealerships that work with them and dont mine basic changes but some are really bad so just do a little research and talk to people in your area to see what they have found to be how your local dealerships operate.
__________________ 2003 Cobra Vert (Redfire) #3938 of 5082 @ 05/27/2003
472rwhp/493rwtq -Modification List - Dyno Sheet 2012 Mustang 3.7L M6 (Kona Blue) 2011 Ford Edge Sport (Red Metallic)
Ok I gotcha, I mean I wasn't gonna do anything just yet but I didn't want to go to the dealer and they say ford won't cover it and be out the money for something I did... I'll check with the dealer and see what they say, thanks for the info