here how it works...whatever OEM part you replace with a 3rd-party part, you lose the warranty coverage on the OEM part you are replacing. You replace the OEM exhaust you lose the exhaust warranty. You replace the cold air you will lose the cold-air warranty. Nissan is under no warranty obligation if your 3rd-party part goes bad for any reason. If anything goes wrong with the engine, Nissan would have to prove that the root cause of the problem was entirely the fault of any 3rd-party part they claim is causing the problem.I am getting ready to do Cat Back Exhaust , Cold Air Intake , and Bully Dog GT ? I dont wanna void the warranty I have a 2010 cc 2x4 with 2000 miles !
The thing you have to watch out for is that Nissan may first try to blame the 3rd-party part without establishing any proof that the 3rd-party part was the entire cause of the engine problem. They are hoping that the customer is ignorant of the consumer regulations (Moss-Magnuson Act). In this case you just threaten getting an attorney. Nissan may then either go ahead and just fix it under the warranty OR they may "impound" the truck on their premises and bring in a Master Mechanic who will proceed to tear the entire engine apart looking for every little thing thay can lay their hat on. It all depends on what the issue is and what is is going to cost them to make the problem go away.
As for the Bully Dog, if you go in with an OEM computer related problem and you somehow expose the fact you run a programmer , Nissan may be able to easily show that the programmer takes the engine out of intended use and / or warranty spec. If they do manage to prove this they will usually make an offer to replace the OEM computer with a new one at totally your part and service expense and then maybe restore your OEM computer warranty on the new OEM computer replacement.
Then its up to you if you want to use the programmer with the new OEM computer. But again the cycle repeats if the new OEM computer blows.