Originally Posted by cappa
This was my next question, if you buy from Ford Racing does this still void the warranty?
Intakes/exhausts are usually ok. Just go cone-air; I wouldn't go cold air unless it never rains (puddles tend to cause issues!).
If you get an ECU tuning that tends to make your warranty go bye-bye.
Suspension and brakes are usually not enough to void anything either, within reason. Like an earlier poster said, it really depends on how flexible your services manager is at the dealership you go to.