Anything that takes the car out of "original equipment specs" can void the warranty. Modifications are a very grey area. It depends on car a car company, but more so on the people who work on the car. I've seen forum posts where a brand new car's warranty was voided because the owner installed different wheels on it. So essentially those mods can void the warranty. Exhaust is a pretty involved modification, I'd be very surprised if the warranty wasn't voided if a Ford rep saw that on a customers car. I'm not sure about how Ford does their own things but BMW doesn't outright void the warranty if the customer purchases the parts through BMW and has their mod certified techs install them.
I was told at my Ford dealer that it only voids the part you change. However I was told that if you get Ford Racing parts or Roush Performance none of the warranty is voided.
Anything that takes the car out of "original equipment specs" can void the warranty. Modifications are a very grey area. It depends on car a car company, but more so on the people who work on the car. I've seen forum posts where a brand new car's warranty was voided because the owner installed different wheels on it. So essentially those mods can void the warranty. Exhaust is a pretty involved modification, I'd be very surprised if the warranty wasn't voided if a Ford rep saw that on a customers car. I'm not sure about how Ford does their own things but BMW doesn't outright void the warranty if the customer purchases the parts through BMW and has their mod certified techs install them.
This is not necessarily true. If you ever have a problem with a manufacture honoring a warranty then you need to contact the Federal Trade Commission, this is who will work on your behalf to keep these big corporations in line when it comes to lemon laws and disputed warranty issues. The only time you will have a problem with a warranty is if they can prove that the aftermarket component that you changed directly caused the failure. If you add a cold air intake and the valve cover starts leaking there is no correlation you'll be covered; however, if you have a problem with the MAF (and you moved it's placement into your new cold air kit) you will not be covered. It is kind of like saying that you changed the tires and your transmission isn't covered anymore... ridiculous. I have personally gone round and round with warranties and Ford in the past and have yet to lose a battle. I have had the FTC involved in more than one instance and they worked hard on my behalf to make things right.
In 2004 we had a brand new Cobra, right around 3,500 miles we blew the IRS into about 10,000 pieces. It had a pulley and drag radials so obviously our fault and not looking for the car to be covered. We swapped to a solid rear axle and it was problem solved, until Ford had to bleed the abs pump with the computer after switching the brakes around. They saw the solid axle and at 3,500 miles voided the warranty on the entire car. This was BS, a call was placed to the FTC and they worked on our behalf to resolve the issue. About 6 months of legal nonsense later, we had our warranty re instated and received a check back from the dealership for a considerable amount of money for breach of warranty claim. The car later went on to have a body control module go bad and some AC problems all which were covered with no questions. The crowning glory was taking the car back to the dealer for a carpeting recall after the 10 roll cage was installed and a fully built proline motor, 3.4l whipple and T/H400 trans. While they made a big not saying that the car could not be test driven we had no issues. Maybe I'm just a stick to my guns kind of guy but don't let a dealership push you around when it comes to your warranty.
Long story short, 50 state legal exhaust and a cold air should have no effect on your warranty.
^^^^^^^ Nice to know. This is the main reason I have not touched the car yet. Didn't know about the warranty and wanted to keep it intact as long as I could.
Magnuson–Moss Warranty Act - Wikipedia, the free encyclopedia
This Federal Law basically states that the manufacturer can not deny warranty coverage because of the installation of aftermarket parts. It is the manufacturer's responsibility to prove that the aftermarket part caused the failure before a warranty claim can be rejected. And as 84Ttop pointed out, that does not void the warranty on the rest of the vehicle.