Here is some info I found about warranty and Headers. When the cat back is done the Hemi is ready for a rude awakening.
WILL IT VOID MY FACTORY WARRANTY?
No, all of our street exhaust products are 50-state street legal. Our headers are 50-state legal and c.a.r.b. approved. In fact, it is illegal for a dealer to deny you the O.E warranty because you have changed the exhaust system. For more details, contact sema, the trade organization of the automotive aftermarket which has been instrumental in protecting such consumer rights, at
www.sema.org and they can refer you to the magnuson-moss warranty act of 1975.
CAN AN AUTOMOTIVE DEALERSHIP VOID YOUR WARRANTY?
Your rights are protected through the Magnuson-Moss Warranty Act, 15 USC, 2302, and the Clean Air Act, 42 USA § 7541.
You have the right to buy high-quality, reliable aftermarket performance and replacement parts – an affordable and convenient alternative to the vehicle maker’s parts.
You have the right to use high-quality aftermarket parts and know that your new car warranty claims will be honored. In fact, your vehicle dealer may not reject a warranty claim simply because an aftermarket product is present. A warranty denial in such circumstances may be proper only if the aftermarket part caused the failure being claimed.
You have the right to patronize independent retail stores for vehicle parts and installation. The U.S. aftermarket offers the world’s finest selection of aftermarket products that satisfy the most discriminating customers seeking personalized vehicles for today’s lifestyle.
If a dealership denies a warranty claim and you think the claim falls under the rules explained above concerning the clean air act (such as an emission part failure), obtain a written explanation of the dealer’s refusal.
If you would like further information on what to do and who to call if your new car warranty is denied, call the Federal Trade Commission at 202-326-3128.
http://www.gibsonperformance.com/faq.asp