A mod cannot void a warranty just because you have on. This includes tunes.

Now, if the car f's up and the tune or mod is proven to be the cause, then the shop has the right to Deny warranty work. But a work denial is not a void because any other faults that are not caused by mods or abusive treatment must still be honored and covered by the warranty

 

cincyguy7185,

Hi, this is Justin with Ford Customer Service. Here are a few sites that you can go to for Ford Mustang parts and accessories:
• FordAccessoriesStore.com
• FordParts.com
• FordRacingParts.com

As with any aftermarket modification to your Mustang, it is important that you consult your local Ford dealership to have these parts or accessories ordered and installed. They can also answer any questions related to warranty and whether or not it may be voided if certain modifications were made.

Thank you,
Justin