Magnuson Moss Act Their is a lot of information about this problem on the internet. The fact is you are protected by federal law under the Magnuson-Moss act regulated by the FTC. The dealer would have to show that your modifications caused the engine to blow as a result of improper use or defect. These engines should work without an exhaust attached to them. Replacing the pipes back to original will probably avoid most of the arguing that you may have to do. I would guess that the dealers would still see that the pipes were changed out at one time. If they do you still have a strong argument to maintain the integrity of your warranty. Remember, they have to show improper use or defects in the 3rd party equipment caused your problem. Here is a site that gives a good overview of the law. http://www.impalaclub.com/naisso/magmoss.htm Just search in google and you can find more including the actual legislature. If you modified your cars computer to accommodate the O2 sensors be sure to put the program back to original. This is where the dealer may have a stronger case. To let you know I sat on the arbitration boards for the better business bureau where we ordered the buy back of cars because the dealer and MFG could not show reasonable cause that the 3rd party product caused the malfunction. Good luck to you hope it all works out because it’s great car.