Your talking about the Magnason-Moss act that only protects consumers on direct replacment parts. Not modifications or changes to the car. Also read in the Magnason Moss Act that they have very limited control over over warranty companies stipulations. Thats why they refer you to your warranty documentation about 100 times. If you talking about being voided for a K&N filter vs. stock then yes they can help. However you replace your stock manifolds with headers the law does nothing to protect you and so on and so forth.