Hi MT. Congratulations on your new Fusion welcome to the Ford Fusion Club.
Concerning "aftermarket stuff" and your warranty; Anything that alters the vehicle and/or vehicle performance in any way, can affect problems and warranty claims related to anything that can be traced back to the modification. Even remotely.
That goes for essentially anything that is not strictly a harmless cosmetic modification. Tuners, CAI modifications/filters, wheels/wheel spacers etc., exhaust systems etc. etc. etc. Even window tint can affect warranty claims on a later problem with the power windows. Of course, everything must be taken on a case by case basis. However, just go in assuming whatever you do can/may/will affect warranty coverage, and life will be easier.
This is all explained in the Warranty Guide we are given as new buyers. If you do not have your copy, you can download the PDF version, along with the Owners Manual and other User Guides, here: https://www.fleet.ford.com/parts-service/resources/owner-manuals/
You can also register your Fusion on the Ford Owners website and find those same manuals and resources here: https://www.ford.com/support/?gclid...wcid=AL!2519!3!267771591263!e!!g!!ford owners
Also, keep in mind that "voiding a warranty" is a wide ranging term that means nothing on the car will never be covered under warranty again. That is a rare occurrence saved for things like salvage vehicles, vehicles caught being used for racing, etc.
The more usual occurrence are things like: A Dealer will find a tuner was used and then a warranty claim for an engine problem may be denied. Or they discover wheel spacers were used and a warranty claim for a bad wheel bearing will be denied, etc. But the warranty is not "voided", and other claims completely unrelated to the modification will be honored.
Hope this information helps and good luck.
